Every free ToolHoney tool in one place — calculators, converters and generators that run in your browser. No sign-up, no downloads, and nothing you type ever leaves your device.
Age Calculator
Find your exact age in years, months and days — plus your next birthday, age on any past or future date, and fun milestones.
Open Age Calculator →BMI Calculator
Work out your Body Mass Index — then go further, with your healthy weight range, BMR, daily calorie targets for your goal, body fat % and ideal weight.
Open BMI Calculator →Date Calculator
Count the days since (or until) any date, find the days between two dates, or add/subtract days, weeks, months and years from a date.
Open Date Calculator →Mortgage Calculator
Work out your monthly mortgage payment, total interest and full payoff schedule — with extra payments, taxes, insurance and PMI.
Open Mortgage Calculator →Volume Calculator
Volume of cylinders, spheres, cones, boxes, pyramids, tanks and more — with every unit and a step-by-step formula breakdown.
Open Volume Calculator →Time Calculator
Add and subtract times, find the time between two moments, convert 12-hour to 24-hour time, and answer "what time will it be in X minutes?".
Open Time Calculator →Calorie Calculator
Your daily calories for losing, maintaining or gaining weight — from BMR and activity level, with macros and a weekly plan.
Open Calorie Calculator →Percentage Calculator
Percentages made painless: what is X% of Y, X is what percent of Y, percentage increase/decrease, and percentage-point changes.
Open Percentage Calculator →Scientific Calculator
A full scientific calculator in your browser: trig, logs, powers, roots, factorials, constants and a history tape — no app needed.
Open Scientific Calculator →Area Calculator
Area of trapezoids, triangles, rectangles, circles, ellipses and more — with diagrams, unit conversion and formula breakdowns.
Open Area Calculator →Image to PDF Converter
Turn JPG and PNG images into a single PDF in your browser — reorder pages, pick page size and orientation, then download.
Open Image to PDF Converter →Compress PDF
Shrink PDF files right in your browser — no uploads, your documents never leave your device.
Open Compress PDF →Auto Loan Calculator
Work out your monthly car payment, total interest and full cost — with down payment, trade-in, sales tax and fees.
Open Auto Loan Calculator →Random Number Generator
Generate random numbers in any range — with no repeats, sorted output and quick-pick presets.
Open Random Number Generator →Dice Roller
Roll any dice — d4 to d100, multiple dice, modifiers and full roll history.
Open Dice Roller →Distance Calculator
Distance between two points, midpoint and slope — in 2D or 3D, with unit conversion.
Open Distance Calculator →Compound Interest Calculator
See how your money grows with compound interest — principal, rate, time, compounding frequency and regular contributions.
Open Compound Interest Calculator →Grade Calculator
Find the final-exam score you need — from your current grade, its weight and the grade you want.
Open Grade Calculator →Day of the Week Calculator
Find what day of the week any date falls on — plus the day number, ISO week and days remaining.
Open Day of the Week Calculator →GPA Calculator
Calculate your GPA from your courses — grades, credit hours, weighted and unweighted, on the 4.0 scale.
Open GPA Calculator →Circle Calculator
Circle area, circumference and diameter from any one measurement — radius, diameter, area or circumference.
Open Circle Calculator →Tip Calculator
Split the bill fairly — tip, total and per-person amounts in one tap.
Open Tip Calculator →Fraction Calculator
Add, subtract, multiply and divide fractions — with simplified answers and mixed numbers.
Open Fraction Calculator →Ounces to Cups Converter
Convert fluid ounces to cups (and back) — US cups, metric cups and spoon measures.
Open Ounces to Cups Converter →Lbs to KG Converter
Convert pounds to kilograms — with stone+lb display and exact conversion factors.
Open Lbs to KG Converter →Roman Numeral Converter
Convert between Roman numerals and numbers — with the full breakdown of each symbol.
Open Roman Numeral Converter →Quadratic Formula Calculator
Solve quadratic equations — roots, discriminant, vertex and step-by-step working.
Open Quadratic Formula Calculator →Currency Converter
Convert between world currencies with live-style rates you control — amount, from, to, and a quick reference table.
Open Currency Converter →Loan Calculator
Work out any loan's monthly payment, total interest and payoff timeline.
Open Loan Calculator →Slope Calculator
Slope between two points — plus intercept, equation, angle and point-slope form.
Open Slope Calculator →Retirement Calculator
See if your retirement savings are on track — current savings, contributions, growth and retirement age.
Open Retirement Calculator →Circumference Calculator
Circumference from radius, diameter or area — with the full formula working.
Open Circumference Calculator →Roth IRA Calculator
Project your Roth IRA growth — contributions, returns and tax-free withdrawals at retirement.
Open Roth IRA Calculator →PDF to Word Converter
Convert PDF to editable Word in your browser — your file is never uploaded.
Open PDF to Word Converter →JPG to JPEG Converter
JPG and JPEG are the same format — re-encode your photos and download them as .jpeg, in your browser.
Open JPG to JPEG Converter →Investment Calculator
Project investment growth with contributions, returns and time — and see the cost of waiting.
Open Investment Calculator →Pythagorean Theorem Calculator
Find the missing side of a right triangle — hypotenuse or leg — with step-by-step working.
Open Pythagorean Theorem Calculator →Sales Tax Calculator
Add or remove sales tax in one step — pre-tax price, tax rate and total, for any region.
Open Sales Tax Calculator →Ratio Calculator
Simplify ratios, scale them up or down, and find missing values in proportions.
Open Ratio Calculator →Word to PDF Converter
Convert Word to real, selectable PDF text in your browser — your file is never uploaded.
Open Word to PDF Converter →TDEE Calculator
Your total daily energy expenditure — BMR times activity level, with calorie targets for losing, maintaining or gaining weight.
Open TDEE Calculator →Inches to CM Converter
Convert inches to cm exactly (1 in = 2.54 cm), with feet+inches input and a quick table.
Open Inches to CM Converter →Ounces to ML Converter
Convert US fluid ounces to ml (1 fl oz = 29.5735 ml), with cups, tablespoons and teaspoons — volume, not weight.
Open Ounces to ML Converter →CM to Inches Converter
Convert cm to inches exactly, with feet+inches and the nearest ruler fraction.
Open CM to Inches Converter →Ovulation Calculator
Predict your fertile window and ovulation day from your cycle — with next 3 cycles shown.
Open Ovulation Calculator →Density Calculator
Density from mass and volume — or find mass or volume when you know the other two.
Open Density Calculator →Square Root Calculator
Square roots with exact simplified form — surds kept exact, plus the decimal value.
Open Square Root Calculator →Salary Calculator
Convert salary between hourly, weekly, monthly and annual pay — with overtime and hours.
Open Salary Calculator →Inflation Calculator
See what your money will be worth in the future — or what it was worth in the past.
Open Inflation Calculator →Acceleration Calculator
Acceleration from change in velocity over time — with distance and final-velocity extras.
Open Acceleration Calculator →Math Calculator
A clean everyday calculator — add, subtract, multiply, divide, percentages and memory, right in your browser.
Open Math Calculator →Statistics Calculator
Mean, median, mode, range, variance and standard deviation from any list of numbers.
Open Statistics Calculator →Standard Deviation Calculator
Standard deviation, step by step — population and sample, with variance and the full working shown.
Open Standard Deviation Calculator →ML to Ounces Converter
Convert ml to fluid ounces (US by default, Imperial in Advanced), with cups and spoon measures.
Open ML to Ounces Converter →Concrete Calculator
How much concrete you need for slabs, footings, columns and stairs — in cubic metres/yards and bags.
Open Concrete Calculator →Pregnancy Calculator
Your due date, current week and trimester from your last period — with milestones along the way.
Open Pregnancy Calculator →Due Date Calculator
Your baby's estimated due date from your last period or conception date — plus conception window.
Open Due Date Calculator →LCM Calculator
Least common multiple of two or more numbers — with prime-factor working shown.
Open LCM Calculator →Compress Image
Compress JPG, PNG and WebP images in your browser — smaller files, same photos, no uploads.
Open Compress Image →Stone to KG Converter
Convert stone (and pounds) to kilograms exactly — with reverse kg to stone+lb display.
Open Stone to KG Converter →Split PDF
Split a PDF into parts by page ranges, every N pages, or one file per page — in your browser.
Open Split PDF →Height Calculator
Convert height between cm, metres, feet+inches and inches — plus predicted adult height from parents' heights.
Open Height Calculator →KG to Lbs Converter
Convert kilograms to pounds — decimal pounds and pounds+ounces, with exact factors.
Open KG to Lbs Converter →Average Calculator
Mean, median, mode and range from any list of numbers — plus weighted average.
Open Average Calculator →Amortization Calculator
Amortisation schedule for any loan — monthly payment, interest split and payoff with extra payments.
Open Amortization Calculator →GCF Calculator
Greatest common factor of two or more numbers — with factor lists and Euclid's steps.
Open GCF Calculator →KG to Stone Converter
Convert kilograms to stone — decimal stone and stone+pounds, with exact factors.
Open KG to Stone Converter →Exponent Calculator
Powers made simple — any base and exponent, including negative and fractional exponents.
Open Exponent Calculator →BMR Calculator
Your basal metabolic rate — Mifflin-St Jeor, Harris-Benedict and Katch-McArdle, compared side by side.
Open BMR Calculator →Resize Image
Resize images by pixels, percentage or preset — aspect lock, no upscaling by default, in your browser.
Open Resize Image →Factor Calculator
All factors of a number, factor pairs and prime factorisation — with division steps.
Open Factor Calculator →Love Calculator
A fun name-compatibility meter — for entertainment only, never real advice.
Open Love Calculator →Percent Error Calculator
Percent error between an observed and a true value — with signed error and accuracy.
Open Percent Error Calculator →Trigonometry Calculator
Sine, cosine, tangent and their inverses — in degrees or radians, plus triangle solving.
Open Trigonometry Calculator →Margin Calculator
Margin, markup and profit from cost and price — with profit-margin formulas explained.
Open Margin Calculator →English to Latin Converter
Translate common English words and phrases to Latin — 366 words and 30 phrases, honestly labelled.
Open English to Latin Converter →MM to Feet Converter
Convert millimetres to feet — decimal feet and feet+inches, with cm/m/inch inputs too.
Open MM to Feet Converter →Feet to CM Converter
Convert feet+inches to centimetres exactly — with reverse cm to feet+inches display.
Open Feet to CM Converter →Triangle Calculator
Solve any triangle — SSS, SAS, ASA or AAS — with all sides, angles, area and perimeter.
Open Triangle Calculator →Time Card Calculator
Weekly time cards — clock-in/out, breaks, overtime and gross pay, shift by shift.
Open Time Card Calculator →Long Division Calculator
Long division with the full step-by-step working — divide, multiply, subtract, bring down.
Open Long Division Calculator →VAT Calculator
VAT calculator — add or remove VAT, net to gross and gross to net, at any rate.
Open VAT Calculator →Conversion Calculator
One converter for everything — length, weight, volume, temperature, time and data units.
Open Conversion Calculator →Body Fat Calculator
Body fat percentage — US Navy method with BMI fallback, plus category and guidance.
Open Body Fat Calculator →Hours Calculator
Hours between two times or two dates — totals in hours, minutes and seconds.
Open Hours Calculator →Right Triangle Calculator
Solve right triangles — any two known values give all sides, angles, area and perimeter.
Open Right Triangle Calculator →ROI Calculator
Return on investment — ROI percentage, annualised return and gain or loss.
Open ROI Calculator →Interest Calculator
Simple and compound interest side by side — interest amount and total payable.
Open Interest Calculator →WEBP to JPG Converter
Convert WEBP images to JPG in your browser — batch, quality control, no uploads.
Open WEBP to JPG Converter →Division Calculator
Division with quotient, remainder, decimal, reduced fraction and mixed number.
Open Division Calculator →Protein Calculator
How much protein you need — daily grams by weight, activity and goal, split per meal.
Open Protein Calculator →Velocity Calculator
Velocity from distance and time — with unit conversion and average velocity.
Open Velocity Calculator →Organize PDF
Organise PDF pages — reorder, delete and rotate pages, then download the new file.
Open Organize PDF →Percent Change Calculator
Percent change between two values — increase or decrease, with the reverse-trip warning.
Open Percent Change Calculator →Mega Millions Payout Calculator
Mega Millions payout estimates — lump sum vs annuity, after federal tax.
Open Mega Millions Payout Calculator →JFIF to JPG Converter
Convert JFIF images to JPG — JFIF is a JPEG container, so this is an honest re-wrap.
Open JFIF to JPG Converter →Tire Size Calculator
Tyre size comparison — diameter, circumference and speedometer error, old vs new.
Open Tire Size Calculator →401K Calculator
401(k) growth projection — contributions, employer match and returns, year by year.
Open 401K Calculator →Hypotenuse Calculator
Hypotenuse from two legs — with angles, perimeter and triple flagging.
Open Hypotenuse Calculator →Hourly Wage Calculator
Hourly wage to annual, monthly and weekly pay — with overtime and reverse conversion.
Open Hourly Wage Calculator →Coin Flip
Flip a virtual coin — single flips, best-of series and full history.
Open Coin Flip →Discount Calculator
Discount calculator — sale price and savings, with stacked discounts and tax.
Open Discount Calculator →Z Score Calculator
Z-score and percentile from value, mean and standard deviation — with interpretation.
Open Z Score Calculator →CAGR Calculator
Compound annual growth rate — from start and end values, with a year-by-year table.
Open CAGR Calculator →Surface Area Calculator
Surface area of cubes, cuboids, spheres, cylinders, cones and pyramids.
Open Surface Area Calculator →Square Calculator
Square properties from any one value — side, area, perimeter or diagonal.
Open Square Calculator →Pace Calculator
Running pace from distance and time — pace per km/mile, speed and race predictions.
Open Pace Calculator →Income Tax Calculator
US federal income-tax estimate — bracket-by-bracket, with marginal and effective rates.
Open Income Tax Calculator →Macro Calculator
Daily macros from calories and goal — protein, carbs and fat in grams and percent.
Open Macro Calculator →PDF to Image Converter
Turn PDF pages into JPG or PNG images in your browser — pick all pages or just a few, at screen, high or print quality. Nothing is uploaded.
Open PDF to Image Converter →Payment Calculator
Work out the monthly payment, total interest and payoff cost of any loan.
Open Payment Calculator →Hour Calculator
Convert hours into seconds, minutes, days and weeks — and convert back again.
Open Hour Calculator →Profit Margin Calculator
Find your profit margin, markup and profit from revenue and cost.
Open Profit Margin Calculator →Time Clock Calculator
Turn clock-in, clock-out and breaks into hours worked and pay.
Open Time Clock Calculator →Body Type Calculator
Estimate your body type and frame size from a few simple measurements.
Open Body Type Calculator →Remainder Calculator
Divide two numbers and see the quotient, remainder and decimal result.
Open Remainder Calculator →Bold Text Generator
Turn plain text into bold Unicode text for social posts and bios.
Open Bold Text Generator →Fahrenheit to Celsius Converter
Convert Fahrenheit to Celsius instantly, with common oven temperatures included.
Open Fahrenheit to Celsius Converter →Powerball Calculator
Estimate Powerball prizes, annuity vs lump sum, and after-tax winnings.
Open Powerball Calculator →Cups to Ounces Converter
Convert cups to fluid ounces (and back) for US cooking measurements.
Open Cups to Ounces Converter →Matrix Calculator
Multiply matrices, find determinants, and score a confusion matrix.
Open Matrix Calculator →Golden Ratio Calculator
Apply the golden ratio (φ ≈ 1.618) to any length, rectangle or design.
Open Golden Ratio Calculator →Celsius to Fahrenheit Converter
Convert Celsius to Fahrenheit instantly, with common oven temperatures included.
Open Celsius to Fahrenheit Converter →Time Duration Calculator
Measure the elapsed time between two clock times, including overnight spans.
Open Time Duration Calculator →SUVAT Calculator
Solve constant-acceleration motion with the SUVAT equations.
Open SUVAT Calculator →House Affordability Calculator
Estimate the house price you can afford from income, debts and rates.
Open House Affordability Calculator →Gematria Calculator
Compute English gematria values — ordinal, reduced and reverse — for any word.
Open Gematria Calculator →BAC Calculator
Estimate blood alcohol concentration (Widmark) and time until sober.
Open BAC Calculator →Annual Income Calculator
Turn hourly pay or a salary into annual, monthly, weekly and daily income.
Open Annual Income Calculator →Arc Length Calculator
Find arc length, sector area and chord length from radius and angle.
Open Arc Length Calculator →Loan Payment Calculator
Work out the monthly payment, total interest and payoff time for any loan, including extra monthly payments.
Open Loan Payment Calculator →Cd Calculator
See how a certificate of deposit grows: future value, interest earned and effective annual yield for any rate and term.
Open Cd Calculator →Potential Energy Calculator
Calculate gravitational and elastic potential energy from mass, height, spring constant and displacement, with unit conversion.
Open Potential Energy Calculator →Quarts to Cups Converter
Convert quarts to cups instantly — plus pints, gallons, fluid ounces, litres and millilitres for cooking and baking.
Open Quarts to Cups Converter →Timesheet Calculator
Add up a two-week timesheet from daily hours: regular hours, overtime hours and gross pay — distinct from clock-in/out shift cards.
Open Timesheet Calculator →Personal Loan Calculator
Price a personal loan properly: monthly payment plus fees, total interest and the true total cost of borrowing.
Open Personal Loan Calculator →Sleep Calculator
Find the best bedtimes for your wake-up time — or the best wake times for your bedtime — using 90-minute sleep cycles.
Open Sleep Calculator →CM to M Converter
Convert centimetres to metres instantly, with millimetres, kilometres, inches, feet and yards alongside.
Open CM to M Converter →Percent Increase Calculator
Find the percent increase (or decrease) between two values, with the difference, ratio and new value as a percent of the old.
Open Percent Increase Calculator →Test Calculator
Run a statistics t-test — one-sample, two-sample (Welch) or paired — with t-statistic, degrees of freedom and p-value.
Open Test Calculator →Bra Size Calculator
Estimate your bra size from underbust and bust measurements, with sister sizes — a starting point, since sizing varies by brand.
Open Bra Size Calculator →Feet to Inches Converter
Convert feet to inches — including heights like 5'4" and 5'5" — with centimetres and metres alongside.
Open Feet to Inches Converter →KM to Miles Converter
Convert kilometres to miles instantly, with metres, feet and yards for distance, running and driving.
Open KM to Miles Converter →Day of Year Calculator
Find what day of the year any date is — plus days remaining, week number and percent of the year elapsed.
Open Day of Year Calculator →Rmd Calculator
Estimate your required minimum distribution from a retirement account using the IRS Uniform Lifetime Table.
Open Rmd Calculator →Sphere Calculator
Find the surface area and volume of a sphere from its radius, with diameter, circumference and cross-section area.
Open Sphere Calculator →Week Calculator
Convert weeks to days, hours, minutes and seconds — and see exactly how many hours are in a week.
Open Week Calculator →Savings Calculator
Project your savings growth: starting balance, monthly deposits, interest rate and time, with total deposits and interest earned.
Open Savings Calculator →Quarts to Gallons Converter
Convert quarts to gallons instantly — plus cups, pints, fluid ounces and litres for cooking and fuel.
Open Quarts to Gallons Converter →Weight Calculator
Convert weight between kilograms, pounds, stone, ounces and grams — a unit converter, not a body-weight tool.
Open Weight Calculator →Miles to KM Converter
Convert miles to kilometres (and back) instantly, with metres, feet and nautical miles too.
Open Miles to KM Converter →Take Home Pay Calculator
Work out your net take-home pay after tax and deductions, by year, month, week and paycheque.
Open Take Home Pay Calculator →Empirical Rule Calculator
Apply the 68-95-99.7 rule to any mean and standard deviation, with z-scores for any value.
Open Empirical Rule Calculator →Simple Interest Calculator
Calculate simple interest and the total amount, with a year-by-year breakdown.
Open Simple Interest Calculator →Median Calculator
Find the median of any list of numbers, with mean, range and sorted order for context.
Open Median Calculator →Rent Vs Buy Calculator
Compare the total cost of renting versus buying over the same period, including mortgage and deposit.
Open Rent Vs Buy Calculator →Scientific Notation Calculator
Convert any number to scientific notation and back, with the mantissa and exponent explained.
Open Scientific Notation Calculator →Minecraft Circle Generator
Generate a pixel-perfect Minecraft circle of any diameter, with a block grid preview and counts.
Open Minecraft Circle Generator →Proportion Calculator
Solve any proportion a:b = c:d for the missing value, with the cross-multiplication shown.
Open Proportion Calculator →Cross Product Calculator
Compute the cross product of two 3D vectors, with magnitude, dot product and the angle between them.
Open Cross Product Calculator →Hours to Days Converter
Convert hours to days, weeks, minutes and seconds — or days back to hours — in one step.
Open Hours to Days Converter →Mg to ML Converter
Convert milligrams to millilitres using the substance's density — water by default, with presets for common liquids.
Open Mg to ML Converter →Rate Of Change Calculator
Find the percentage change between two values, with the absolute change and per-period rate.
Open Rate Of Change Calculator →Wavelength Calculator
Convert between frequency and wavelength for any wave, with the electromagnetic band identified.
Open Wavelength Calculator →Superscript Generator
Turn ordinary text into superscript unicode — perfect for powers, exponents and footnotes — and copy it anywhere.
Open Superscript Generator →Subnet Calculator
Work out a network's address, broadcast, usable hosts and IP range from any IP and CIDR.
Open Subnet Calculator →Months Calculator
Convert between days, months and years in both directions, and add months to a date.
Open Months Calculator →Heart Rate Zone Calculator
Find your five heart-rate training zones from age and resting heart rate, using Karvonen and max-HR methods.
Open Heart Rate Zone Calculator →One Rep Max Calculator
Estimate your one-rep max from any lift, with Epley and Brzycki formulas and a full percentage table.
Open One Rep Max Calculator →Inch to CM Converter
Convert inches to centimetres instantly, with the exact 2.54 factor and a reverse centimetre-to-inch mode.
Open Inch to CM Converter →WEBP to PNG Converter
Convert WEBP images to PNG in your browser — lossless, with transparency preserved and nothing uploaded.
Open WEBP to PNG Converter →Body Shape Calculator
Estimate your body shape from bust, waist and hip measurements, with waist-to-hip and waist-to-height ratios.
Open Body Shape Calculator →Square Footage Calculator
Work out square footage for rectangles, circles and triangles, in feet, inches, metres or yards.
Open Square Footage Calculator →Mileage Calculator
Calculate fuel mileage (MPG / km per litre), trip fuel cost and cost per mile from distance and fuel used.
Open Mileage Calculator →Duration Calculator
Find the elapsed time between two dates and times, broken down into days, hours, minutes and seconds.
Open Duration Calculator →Triangular Prism Calculator
Calculate the volume and surface area of a triangular prism from its triangular base and length.
Open Triangular Prism Calculator →Pregnancy Week Calculator
Find your current pregnancy week, trimester and estimated due date from the first day of your last period.
Open Pregnancy Week Calculator →Dew Point Calculator
Calculate the dew point from temperature and humidity, with comfort guidance and absolute humidity.
Open Dew Point Calculator →PayPal Fee Calculator
Estimate PayPal fees and net received for standard, micropayment and international payments.
Open PayPal Fee Calculator →Financial Calculator
Solve any one time-value-of-money variable — present value, future value, payment, rate or number of periods.
Open Financial Calculator →PNG to JPG Converter
Convert PNG images to JPG in your browser, with quality control and a background colour for transparent areas.
Open PNG to JPG Converter →Frequency Calculator
Calculate relative frequency from counts, and wave frequency, period and wavelength from each other.
Open Frequency Calculator →Probability Calculator
Calculate unions, intersections, complements and conditional probabilities for two events.
Open Probability Calculator →Refinance Calculator
Compare your current loan with a refinance offer: new payment, monthly saving and break-even time.
Open Refinance Calculator →Lbs to Stone Converter
Convert pounds to stone and pounds, with kilograms, for weights, body weight and luggage.
Open Lbs to Stone Converter →Apy Calculator
Convert a nominal interest rate to APY (effective annual yield) for any compounding frequency.
Open Apy Calculator →Protein Intake Calculator
Estimate recommended daily protein intake from body weight, activity and goal, split per meal.
Open Protein Intake Calculator →Diagonal Calculator
Find the diagonal of a rectangle, square or box from its side lengths, with aspect ratio.
Open Diagonal Calculator →Percentage Difference Calculator
Calculate percentage difference, percentage increase and decrease between two numbers.
Open Percentage Difference Calculator →Net Ionic Equation Calculator
Balance common aqueous reactions and derive the molecular, complete ionic and net ionic equations — with spectator ions cancelled and clear limits on supported reactions.
Open Net Ionic Equation Calculator →Map Calculator
A map scale calculator: convert map distances to real distances, real distances to map distances, or find the scale itself.
Open Map Calculator →Constant of Proportionality Calculator
Find the constant of proportionality k from x and y values, check whether a table is truly proportional, and predict new values with y = kx.
Open Constant of Proportionality Calculator →Work Hours Calculator
An hours-worked calculator for a single shift: start and end times, unpaid breaks, overtime and pay — distinct from a weekly time card or pay-period timesheet.
Open Work Hours Calculator →Jfif to PDF Converter
Convert JFIF and JPG images into a single PDF in your browser — multi-image, page size and orientation options, fully client-side and private.
Open Jfif to PDF Converter →Period Calculator
Predict your next period, fertile window and ovulation date from your last period and cycle length — an estimate for planning, not a contraceptive method.
Open Period Calculator →Resistor Color Code Calculator
Decode resistor colour bands into ohms and tolerance, or enter a resistance value to find its colour bands — 4, 5 and 6-band resistors.
Open Resistor Color Code Calculator →Log Calculator
Calculate logarithms to any base — including log base 2, natural log and log base 10 — plus antilogs and change-of-base conversions.
Open Log Calculator →ML to Cups Converter
Convert millilitres to cups (US, US legal, metric and imperial) and back, with tablespoons, teaspoons and fluid ounces for recipes.
Open ML to Cups Converter →Ejection Fraction Calculator
Calculate ejection fraction from end-diastolic and end-systolic volumes, with stroke volume, cardiac output and an interpretation band — an estimate, not medical advice.
Open Ejection Fraction Calculator →Square Feet Calculator
Calculate square footage for rectangles, circles and triangles in feet, inches or metres, with square metres, square yards and acres alongside.
Open Square Feet Calculator →Password Generator
Generate strong random passwords with cryptographically secure randomness (crypto.getRandomValues, never Math.random), with length, character sets and a strength meter.
Open Password Generator →Annuity Calculator
Calculate the future value, present value or payment of an annuity — ordinary or due — with any payment frequency and growth option.
Open Annuity Calculator →Work Calculator
Solve the work equation W = F × d × cos(θ): find work, force, distance or power, with newtons/pounds-force and metres/feet conversions.
Open Work Calculator →Exponential Growth Calculator
Model exponential growth and decay: future value, growth rate from two values, doubling time and a year-by-year projection table.
Open Exponential Growth Calculator →Home Equity Loan Calculator
Work out your available home equity, the maximum home equity loan at a given loan-to-value limit, and its monthly payment.
Open Home Equity Loan Calculator →Monthly Payment Calculator
A generic monthly payment calculator for any loan type — personal, auto, home or other — with extra payments, total interest and payoff date, answer first.
Open Monthly Payment Calculator →Midpoint Calculator
Find the midpoint of a line segment, with its length, slope and equation — in 2D, or in 3D under Advanced options.
Open Midpoint Calculator →Inches to M Converter
Convert inches to metres (and metres back to inches), including fractional inches like 5 1/2, with feet, centimetres and yards alongside.
Open Inches to M Converter →APR Calculator
Work out the true yearly cost of a loan — APR and effective rate, with fees included, from the rate or from the payment.
Open APR Calculator →ACFT Calculator
Score the Army Combat Fitness Test's six events — deadlift, power throw, push-ups, sprint-drag-carry, plank and 2-mile run — by age and gender, with pass/fail per event.
Open ACFT Calculator →Age Difference Calculator
How far apart are two people in age? Enter two birth dates and get the exact gap in years, months and days — plus who is older and by how much.
Open Age Difference Calculator →Angle Calculator
The angle between two vectors in 2D or 3D — or the acute angle between two lines from their slopes.
Open Angle Calculator →Angular Velocity Calculator
Angular velocity from angle and time — in radians and degrees per second, plus frequency, period, RPM and tangential speed.
Open Angular Velocity Calculator →Annuity Payout Calculator
Turn a lump sum into a monthly income: enter what you have, how long it must last and the growth rate, and get the payout — with or without growth.
Open Annuity Payout Calculator →Antilog Calculator
Antilogarithms in base 10, e, 2 or any custom base — with the log/antilog round-trip shown.
Open Antilog Calculator →Average Atomic Mass Calculator
Isotope masses and their abundances, weighted into one average atomic mass — the number behind every periodic-table weight.
Open Average Atomic Mass Calculator →Avif to JPG Converter
Convert AVIF images to JPG in your browser — nothing is uploaded. AVIF decoding depends on your browser: Chrome, Edge, Firefox and Safari 16.1+ support it, and older browsers will tell you plainly if they cannot.
Open Avif to JPG Converter →Binary Calculator
Binary arithmetic and base conversion — add, subtract, multiply and divide in binary, or convert between binary, decimal, hex and octal.
Open Binary Calculator →Board Foot Calculator
Price lumber the way sawmills do: enter board thickness, width, length and quantity to get board feet — and the total cost.
Open Board Foot Calculator →Budget Calculator
Income versus spending by category — totals, what is left over, your savings rate, and the 50/30/20 targets for your income.
Open Budget Calculator →Calories Burned Calculator
How many calories does an activity actually burn? Pick an activity, enter your weight and time, and get the energy cost — walking speeds included.
Open Calories Burned Calculator →Cap Rate Calculator
Capitalisation rate from net operating income and property value — with a full expense breakdown and gross rent multiplier.
Open Cap Rate Calculator →Centripetal Force Calculator
F = mv²/r — centripetal force from mass, speed and radius, or from angular velocity, with acceleration and g-force shown too.
Open Centripetal Force Calculator →Common Denominator Calculator
The lowest common denominator of two or three fractions, with every fraction rewritten as an equivalent fraction over it — and their sum.
Open Common Denominator Calculator →Confidence Interval Calculator
Build a confidence interval for a mean from sample mean, standard deviation and size — or for a proportion — with z or t critical values chosen for you.
Open Confidence Interval Calculator →CPM Calculator
Advertising cost per 1,000 impressions — solve for CPM, campaign cost or impressions. Leave the value you want to find blank.
Open CPM Calculator →Credit Card Interest Calculator
Work out credit card interest from APR with the average daily balance method — daily periodic rate, interest for the billing period, and how long a fixed payment takes to clear a balance.
Open Credit Card Interest Calculator →Credit Card Payoff Calculator
How long a credit-card balance takes to clear at a fixed monthly payment — months, total interest, and what an extra payment saves.
Open Credit Card Payoff Calculator →Crop Image
Crop photos in your browser — drag and resize the crop box or pick an aspect preset, then download PNG, JPEG or WebP. Files never leave your device.
Open Crop Image →Cubic Yard Calculator
Work out how many cubic yards of concrete, gravel, soil or mulch you need from length, width and depth — plus bag counts and weight in tons.
Open Cubic Yard Calculator →Cups to Pound Converter
How many cups in a pound? It depends on the ingredient — convert cups to pounds (and back) using real ingredient densities, or enter a custom density.
Open Cups to Pound Converter →Cups to Quarts Converter
Convert cups to quarts (and back) with pints, gallons, millilitres and tablespoons shown for US, metric and UK cups.
Open Cups to Quarts Converter →Decimal Calculator
Exact decimal arithmetic — add, subtract, multiply and divide without the 0.1 + 0.2 = 0.30000000000000004 floating-point error.
Open Decimal Calculator →Degrees Of Freedom Calculator
Degrees of freedom for t-tests, chi-square tests and one-way ANOVA — pick the test, enter the sample sizes, get the DF and what it means.
Open Degrees Of Freedom Calculator →Dilution Calculator
Solve C1V1 = C2V2 for any missing value, or plan a serial dilution — how concentration falls step by step.
Open Dilution Calculator →Download Time Calculator
File size plus connection speed equals download time — with MB vs MiB handled properly and a realistic-speed estimate.
Open Download Time Calculator →DTI Calculator
Front-end and back-end debt-to-income ratios — with lender thresholds and how much housing payment your income supports.
Open DTI Calculator →eDPI Calculator
Effective DPI for gaming: mouse DPI times in-game sensitivity — plus the sensitivity you need at any other DPI to match it.
Open eDPI Calculator →Excel to PDF Converter
Convert Excel spreadsheets to PDF in your browser — nothing is uploaded. Only the first sheet is converted, as values: formatting, charts and images are not carried over.
Open Excel to PDF Converter →Expiry Date Calculator
Manufacture or opening date plus shelf life equals the expiry date — with days remaining and a use-by warning window.
Open Expiry Date Calculator →Feet to M Converter
Convert feet to metres, feet + inches to metres, or metres back to feet and inches — with the exact international foot.
Open Feet to M Converter →Feet to Miles Converter
Feet into miles, kilometres, metres and yards — the 5,280 divisor, done for you.
Open Feet to Miles Converter →Feet to Yard Converter
How many feet in a yard? 3. Convert feet to yards instantly, with inches, miles, metres and centimetres alongside.
Open Feet to Yard Converter →FFMI Calculator
Fat-Free Mass Index from weight, height and body-fat % — plus the height-normalised FFMI and an honest interpretation against the natural limit.
Open FFMI Calculator →FHA Loan Calculator
Estimate an FHA mortgage payment: 3.5% down, the 1.75% upfront mortgage insurance premium financed into the loan, and monthly MIP included.
Open FHA Loan Calculator →Force Calculator
Solve F = ma, weigh anything on Earth, the Moon, Mars or Jupiter, or work out net force and the acceleration it produces.
Open Force Calculator →Gas Calculator
Trip fuel cost — distance, consumption and fuel price, with cost per mile or kilometre and a split between passengers.
Open Gas Calculator →Gravel Calculator
Gravel for a driveway or path — area and depth to cubic yards, weight in tons, and how many bags you need.
Open Gravel Calculator →HELOC Calculator
Your home equity line of credit limit, draw-period payment and full repayment payment — from your home value, mortgage balance and rate.
Open HELOC Calculator →HELOC Payment Calculator
Work out your HELOC payments in both phases — interest-only during the draw period, then fully amortising through repayment.
Open HELOC Payment Calculator →Hexagon Calculator
Solve a regular hexagon from any one measurement — side, area, perimeter, apothem or a diagonal — with every other measurement worked out.
Open Hexagon Calculator →Hours to Minutes Converter
Hours into minutes, seconds, days and weeks — one input, every scale.
Open Hours to Minutes Converter →Image to JPG Converter
Convert PNG, WEBP, GIF or BMP images to JPG in your browser — with a quality slider and a background colour for transparent areas. JPG is JPEG, so this also covers image-to-JPEG searches.
Open Image to JPG Converter →Interest Rate Calculator
Solve for the interest rate — on a loan from its payment, or on an investment from its growth. Nominal and effective rates included.
Open Interest Rate Calculator →Interpolation Calculator
Linear interpolation between two known points — plus extrapolation warnings and the inverse solve (find x for a given y).
Open Interpolation Calculator →IRA Calculator
Traditional IRA growth calculator: regular contributions, annual return and years to retirement, with the after-tax value of withdrawals shown.
Open IRA Calculator →JPEG to PNG Converter
Convert JPEG images to PNG in your browser — nothing is uploaded. PNG is lossless, so the converted file is usually larger than the JPEG.
Open JPEG to PNG Converter →JPG to PNG Converter
Convert JPG images to PNG in your browser — nothing is uploaded. PNG is lossless, so the converted file is usually larger than the JPG.
Open JPG to PNG Converter →JPG to WEBP Converter
Convert JPG images to WEBP in your browser — nothing is uploaded. WEBP files are much smaller than JPG at the same visual quality.
Open JPG to WEBP Converter →Kilometer Calculator
The kilometre, converted every way: metres, centimetres, miles, yards, feet and inches — plus walking and driving times for the distance.
Open Kilometer Calculator →KM to M Converter
Convert kilometres to metres instantly — with centimetres, millimetres, miles, yards and feet alongside.
Open KM to M Converter →Lbs to G Converter
Pounds to grams with the exact avoirdupois factor — plus kilograms, ounces and the reverse grams-to-pounds direction.
Open Lbs to G Converter →LDL Calculator
Estimate LDL ('bad') cholesterol from total cholesterol, HDL and triglycerides — by the classic Friedewald equation and the newer Martin–Hopkins method.
Open LDL Calculator →Liters to Gallon Converter
Convert litres to gallons — US and UK gallons side by side, clearly labelled, so you never mix them up.
Open Liters to Gallon Converter →Lottery Calculator
Odds for any pick-N-from-M lottery: jackpot odds, match-3/4/5 odds and the expected value of a ticket.
Open Lottery Calculator →Lottery Annuity Calculator
Any lottery jackpot, as an annuity or lump sum: graduated yearly payments, cash value and after-tax totals for any game.
Open Lottery Annuity Calculator →Merge PDF
Merge several PDFs into one file in your browser — reorder them first, nothing uploaded.
Open Merge PDF →Million to Lakh Converter
Indian numbering made exact: millions, lakhs, crores and billions converted both ways, with Indian digit grouping.
Open Million to Lakh Converter →Minutes to Hours Converter
Convert minutes into hours and minutes, decimal hours and days — or go the other way, from hours back to minutes.
Open Minutes to Hours Converter →ML to G Converter
Convert millilitres to grams by density — water by default, common kitchen substances, or your own density. Also converts grams back to millilitres.
Open ML to G Converter →ML to Mg Converter
Convert millilitres to milligrams with the liquid's density — water, milk, oil, honey and more, or a custom density. The reverse direction lives in the mg-to-ml converter.
Open ML to Mg Converter →MM to CM Converter
Millimetres to centimetres — how many mm in a cm, both directions, with metres, inches and feet alongside.
Open MM to CM Converter →MM to Inches Converter
Convert millimetres to inches — exactly, to feet and inches, and to centimetres and metres — with a quick reference table for common sizes.
Open MM to Inches Converter →MM to M Converter
Convert millimetres to metres instantly — with centimetres, kilometres, inches, feet and yards alongside.
Open MM to M Converter →Molarity Calculator
Solve molarity, moles, mass or solution volume: enter any three values and the fourth is calculated, with molar mass handled for you.
Open Molarity Calculator →Molecular Weight Calculator
Type any chemical formula — H2O, C6H12O6, Ca(OH)2 — and get its molar mass plus the mass percentage of every element.
Open Molecular Weight Calculator →Money Calculator
Count coins and bills to a total — enter how many of each denomination you have and get the total, split by bills and coins.
Open Money Calculator →MPG Calculator
Miles per gallon from distance and fuel used — with L/100km, km per litre and cost per mile alongside.
Open MPG Calculator →Nutrition Calculator
Full daily nutrition targets from your body and goal — calories, protein, carbs, fat, fibre, sugar limit, sodium and water, not just macros.
Open Nutrition Calculator →P-Value Calculator
Turn a z-score or t-statistic into a p-value — one-tailed or two-tailed — with a plain-English read on statistical significance.
Open P-Value Calculator →Percent Yield Calculator
Percent yield from actual and theoretical yield — with the amount lost, and what an over-100% result usually means.
Open Percent Yield Calculator →Perimeter Calculator
The perimeter of a square, rectangle, triangle, circle, regular polygon or ellipse — with the formula shown and the triangle inequality checked.
Open Perimeter Calculator →Pint to Cups Converter
How many cups in a pint — US and UK pints, labelled, with millilitres, litres and the other system's cups alongside.
Open Pint to Cups Converter →Pints to Gallon Converter
How many pints in a gallon? 8 — in both the US and UK systems, but the gallons differ, so the litres don't. Convert both, labelled.
Open Pints to Gallon Converter →PNG to WEBP Converter
Convert PNG images to WEBP in your browser — nothing is uploaded. WEBP keeps transparency and is usually far smaller than PNG.
Open PNG to WEBP Converter →Poisson Distribution Calculator
Poisson probabilities: P(X = k), cumulative P(X <= k) and P(X >= k), with mean and variance both equal to lambda.
Open Poisson Distribution Calculator →Pounds to Stone Converter
Convert pounds into stone and pounds — the way body weight is quoted in the UK — with kilograms and ounces alongside.
Open Pounds to Stone Converter →Power Calculator
Power from work and time, force and speed, or voltage and current — with watts, kilowatts and horsepower together.
Open Power Calculator →PPP Calculator
Purchasing Power Parity: what a salary or amount in one country is really worth in another, using World Bank price-level indices — plus the market-rate comparison.
Open PPP Calculator →Price Elasticity Of Demand Calculator
Midpoint-method price elasticity: how much quantity demanded moves when price moves — elastic, inelastic or unitary, with both percentage changes shown.
Open Price Elasticity Of Demand Calculator →Quarts to Cup Converter
How many quarts in a cup — and cups in a quart — in US and UK measures, with millilitres and litres alongside.
Open Quarts to Cup Converter →Roof Pitch Calculator
Turn roof rise and run into pitch (x-in-12), angle in degrees, slope percentage and rafter length — the numbers roofers actually use.
Open Roof Pitch Calculator →Rounding Calculator
Round to decimal places or significant figures — half-up, half-even (banker's), half-down, ceiling and floor, side by side.
Open Rounding Calculator →Seconds to Hours Converter
Seconds into hours, minutes, days and weeks — plus a plain h/m/s breakdown.
Open Seconds to Hours Converter →Shelf Life Calculator
How long food lasts in the pantry, fridge or freezer — pick an item and a storage method and get its use-by date and days remaining.
Open Shelf Life Calculator →Sig Fig Calculator
Count significant figures, round to any number of sig figs, or do addition, subtraction, multiplication and division with the correct sig-fig rules applied.
Open Sig Fig Calculator →Stair Calculator
Plan a straight flight of stairs from your total rise and run — riser count and height, tread depth, stringer length and stair angle, with code guidance flags.
Open Stair Calculator →Steps to Miles Converter
Turn your step count into miles and kilometres — with a stride length estimated from your height, or your own measured stride.
Open Steps to Miles Converter →Stock Average Calculator
Your average cost across multiple stock purchases — with total invested, current value and gain or loss per lot and overall.
Open Stock Average Calculator →Student Loan Calculator
Student loan repayment — standard monthly payment, payoff date, and how much extra payments save in interest and time.
Open Student Loan Calculator →SVG to PNG Converter
Turn any SVG graphic into a PNG image in your browser — upload a file or paste SVG code, pick the size and background, then download the PNG. Nothing is uploaded anywhere.
Open SVG to PNG Converter →Vertex Calculator
Find the vertex and axis of symmetry of a parabola from standard, vertex or factored form — with the vertex form of the equation worked out for you.
Open Vertex Calculator →VO2 Max Calculator
Estimate your VO2 max — the headline measure of aerobic fitness — from a Cooper run, a resting heart rate, or the Rockport walk test, with an age and sex rating.
Open VO2 Max Calculator →Voltage Drop Calculator
Voltage drop over a cable run — single or three phase, copper or aluminium — with the percentage drop and the NEC guidance it falls under.
Open Voltage Drop Calculator →Weight Loss By Date Calculator
Pick a target weight and a target date, and find the weekly loss rate and daily calorie deficit it requires — with a clear warning when the pace is too fast.
Open Weight Loss By Date Calculator →Wet Bulb Temperature Calculator
Wet-bulb temperature from air temperature and humidity (Stull formula) — with heat-stress guidance and the Fahrenheit equivalent.
Open Wet Bulb Temperature Calculator →Yards to Mile Converter
How many yards in a mile? 1,760. Convert yards to miles instantly, with kilometres, metres, feet and inches alongside.
Open Yards to Mile Converter →HEIC to JPG Converter
Turn iPhone HEIC photos into JPGs in your browser — decoded with libheif, so it works in any browser, not just Safari.
Open HEIC to JPG Converter →WEBP to PDF Converter
Turn WEBP images into a single PDF in your browser — reorder pages, pick page size and orientation, then download.
Open WEBP to PDF Converter →DOCX to PDF Converter
Turn Word documents into a clean PDF in your browser — text extracted and laid out for reading and printing.
Open DOCX to PDF Converter →EPUB to PDF Converter
Turn DRM-free e-books into a printable PDF in your browser — chapters in reading order, headings in bold.
Open EPUB to PDF Converter →BMP to PDF Converter
Turn BMP images into a single PDF in your browser — reorder pages, pick page size and orientation, then download.
Open BMP to PDF Converter →JPG to DOC Converter
Embed JPG photos into a genuine editable .docx document in your browser — pictures only, no OCR text extraction.
Open JPG to DOC Converter →AVIF to PNG Converter
Turn AVIF images into PNGs in your browser — full quality, transparency kept, with a clear error if decoding fails.
Open AVIF to PNG Converter →PNG to ICO Converter
Turn PNG images into genuine .ico files in your browser — with 16, 32 and 48 pixel versions for favicons and app icons.
Open PNG to ICO Converter →PDF to CSV Converter
Extract tables from text-based PDFs into a spreadsheet-ready CSV in your browser — properly escaped, comma or semicolon.
Open PDF to CSV Converter →PDF to PPT Converter
Turn each PDF page into a slide in a genuine .pptx in your browser — clean editable text slides you can restyle.
Open PDF to PPT Converter →45 45 90 Triangle Calculator
Solve a 45-45-90 triangle from any one value — leg, hypotenuse, area or perimeter — with exact x√2 forms.
Open 45 45 90 Triangle Calculator →Significant Figures Calculator
Count significant figures in any number and round to any number of significant figures, including scientific notation.
Open Significant Figures Calculator →Intercept Calculator
Find the x-intercept and y-intercept of a line from slope-intercept form, standard form or two points.
Open Intercept Calculator →Stone to Lbs Converter
Convert stone to pounds (and back) with the exact 1 stone = 14 lb factor, plus the kilogram equivalent.
Open Stone to Lbs Converter →CM to MM Converter
Convert centimetres to millimetres (and back) with the exact 1 cm = 10 mm factor, plus metres and inches.
Open CM to MM Converter →KG to Ounces Converter
Convert kilograms to ounces (and back) with the exact avoirdupois factor, plus pounds and grams.
Open KG to Ounces Converter →Liter to KG Converter
Convert litres to kilograms for any liquid — pick the substance density or enter your own; water defaults to 1.00.
Open Liter to KG Converter →How Much Water Calculator
Estimate how much water to drink a day from your weight, activity, climate and exercise — in litres, glasses and bottles.
Open How Much Water Calculator →Endpoint Calculator
Find the missing endpoint of a line segment from its midpoint and the other endpoint, with a midpoint check.
Open Endpoint Calculator →Binomial Distribution Calculator
Binomial probabilities: exact P(X = k), cumulative probabilities, mean, variance and the normal-approximation check.
Open Binomial Distribution Calculator →RV Loan Calculator
RV loan payments with down payment, trade-in, sales tax and fees — plus total interest and an extra-payment payoff summary.
Open RV Loan Calculator →Net Run Rate Calculator
Cricket net run rate with correct overs-to-balls conversion (49.3 = 49.5 overs) and the all-out quota rule explained.
Open Net Run Rate Calculator →Alcohol Elimination Calculator
Widmark estimate of BAC and time until alcohol leaves your system — estimate only, never a fitness-to-drive guarantee.
Open Alcohol Elimination Calculator →Grams to ML Converter
Convert grams to millilitres for any liquid — pick the substance density or enter your own; water is 1:1.
Open Grams to ML Converter →Gallons to Quarts Converter
Convert gallons to quarts (and back) for US and Imperial gallons, with litres and pints to remove any doubt.
Open Gallons to Quarts Converter →Unit Price Calculator
Compare 2–3 products by price per unit and see the best-value verdict with the percentage saved.
Open Unit Price Calculator →KG to Liters Converter
Convert kilograms to litres for any liquid — pick the substance density or enter your own; water is 1:1.
Open KG to Liters Converter →NPV Calculator
Net present value for uneven multi-year cash flows, with IRR, present value of inflows and undiscounted payback.
Open NPV Calculator →Standard Form to Vertex Calculator
Convert a parabola from standard form y = ax² + bx + c to vertex form and read off its vertex, axis of symmetry and roots.
Open Standard Form to Vertex Calculator →Partial Pressure Calculator
Apply Dalton's law: find each gas's partial pressure from its mole fraction and the total pressure of the mixture.
Open Partial Pressure Calculator →Weight Gain Calculator
Estimate the daily calories you need to gain weight steadily, from your maintenance calories plus a safe weekly surplus.
Open Weight Gain Calculator →CPI Calculator
Adjust money for inflation between two CPI values — see what a past amount is worth today, or what today's amount was worth then.
Open CPI Calculator →Gear Ratio Calculator
Work out a gear ratio from driver and driven teeth, with output speed and torque — plus multi-stage ratios in Advanced.
Open Gear Ratio Calculator →Dunk Calculator
How high do you need to jump to dunk? Enter your standing reach and the calculator works out the vertical jump required.
Open Dunk Calculator →Puppy Weight Calculator
Estimate your puppy's adult weight from its current weight, age and breed size — with the range to expect, not just one number.
Open Puppy Weight Calculator →Slope Intercept Form Calculator
Get the slope-intercept equation y = mx + b from a slope and intercept, or from two points — with intercepts and angle.
Open Slope Intercept Form Calculator →Chemistry Calculator
Find the molar mass of any chemical formula — with parentheses support — or look up a single element's atomic mass.
Open Chemistry Calculator →ML to KG Converter
Convert millilitres to kilograms for real substances — water, milk, oil, honey and more — using each one's density.
Open ML to KG Converter →Expected Value Calculator
Find the expected value, variance and standard deviation of a gamble or decision from its outcomes and probabilities.
Open Expected Value Calculator →Recurring Deposit Calculator
Work out what a monthly recurring deposit grows to — maturity value, total deposited and interest earned.
Open Recurring Deposit Calculator →Soil Calculator
How much soil do you need? Enter your bed's size and depth to get cubic feet, cubic yards and bags required.
Open Soil Calculator →Pounds to Gallon Converter
Convert pounds to gallons for real liquids — water, milk, oil, honey and more — using each one's weight per gallon.
Open Pounds to Gallon Converter →Pay Raise Calculator
Work out your new pay after a raise — by percentage or by new rate — with the increase per hour, month and year.
Open Pay Raise Calculator →Brick Calculator
Estimate bricks, mortar and waste allowance for a wall from its size, brick size and mortar joint.
Open Brick Calculator →Concentration Calculator
Work out molarity from moles and volume, or solve a dilution with C1V1 = C2V2 — find whichever value is missing.
Open Concentration Calculator →Wallpaper Calculator
How many rolls of wallpaper do you need? Enter the room, the roll size and the pattern repeat to find out.
Open Wallpaper Calculator →Download Speed Calculator
Work out the download speed you need for a file and deadline — or how long a download will take on your connection.
Open Download Speed Calculator →Kinetic Energy Calculator
Find the kinetic energy and momentum of any moving object, in any mass and speed units.
Open Kinetic Energy Calculator →Nether Portal Calculator
Convert Minecraft coordinates between the Overworld and the Nether with the 8:1 ratio.
Open Nether Portal Calculator →Win Percentage Calculator
Turn any win-loss-tie record into a win percentage, games behind, and the winning run needed to hit a target.
Open Win Percentage Calculator →Lbs to Cups Converter
Convert pounds to US cups for any ingredient — flour, sugar, butter, honey and more.
Open Lbs to Cups Converter →Mole Calculator
Convert between grams, moles and particle counts using molar mass and Avogadro's number.
Open Mole Calculator →Circle Skirt Calculator
Work out the waist radius, fabric radius and yardage for a full circle skirt.
Open Circle Skirt Calculator →Cups to Lbs Converter
Convert US cups to pounds for any ingredient — flour, sugar, butter, honey and more.
Open Cups to Lbs Converter →Parallel Resistor Calculator
Find the equivalent resistance of 2–6 resistors in parallel, with current shares and power.
Open Parallel Resistor Calculator →Least Squares Regression Calculator
Fit a least-squares regression line to your data — slope, intercept, correlation and predictions.
Open Least Squares Regression Calculator →Dot Product Calculator
Compute the dot product of 2D or 3D vectors, plus the angle between them.
Open Dot Product Calculator →Gallons to Lbs Converter
Convert US gallons to pounds for water, fuel, milk, honey and more.
Open Gallons to Lbs Converter →Lean Body Mass Calculator
Estimate lean body mass with the Boer, James and Hume formulas, plus implied body fat.
Open Lean Body Mass Calculator →Solar Panel Calculator
Size a home solar system: panels needed, system size and estimated annual output from your bill.
Open Solar Panel Calculator →Pipe Weight Calculator
Work out pipe weight from outside diameter, wall thickness, length and material — including MS pipe.
Open Pipe Weight Calculator →Audiobook Speed Calculator
Find how long an audiobook takes at any playback speed — and how much time you save.
Open Audiobook Speed Calculator →Board Feet Calculator
Calculate board feet for any lumber size and quantity, with an optional cost estimate.
Open Board Feet Calculator →Scale Factor Calculator
Convert dimensions between real and model sizes at any scale, with area and volume scaling.
Open Scale Factor Calculator →Grams to Ounces Converter
Convert grams to ounces with the exact avoirdupois factor, plus kilograms and pounds.
Open Grams to Ounces Converter →Net Force Calculator
Solve Newton's second law for force, mass or acceleration from any two values.
Open Net Force Calculator →Curvature Calculator
Find the curvature of a curve at a point for parabolas, cubics, sine, cosine and exponentials.
Open Curvature Calculator →Dosage Calculator
Work out weight-based doses in mg per dose and per day, with optional liquid volume and maximum-dose checks.
Open Dosage Calculator →Electron Configuration Calculator
Get any element's full and noble-gas electron configuration, with Aufbau exceptions flagged.
Open Electron Configuration Calculator →Radical Calculator
Simplify square roots and add, subtract or multiply radicals, with like-term handling.
Open Radical Calculator →Watt Calculator
Solve P = VI for power, voltage or current, and turn watts and hours into kilowatt-hours.
Open Watt Calculator →Batting Average Calculator
Batting averages for cricket (runs per dismissal) and baseball (hits per at-bat), in scorecard format.
Open Batting Average Calculator →Mean Arterial Pressure Calculator
Mean arterial pressure from systolic and diastolic readings, with pulse pressure alongside.
Open Mean Arterial Pressure Calculator →Drywall Calculator
Estimate drywall sheets, screws, joint compound and tape from wall area.
Open Drywall Calculator →Point Slope Form Calculator
Turn a point and a slope into point-slope, slope-intercept and standard forms.
Open Point Slope Form Calculator →GDP Calculator
GDP by the expenditure approach, with net exports and GDP per capita.
Open GDP Calculator →Rational Number Calculator
Simplify fractions and add, subtract, multiply or divide rational numbers in lowest terms.
Open Rational Number Calculator →Point Estimate Calculator
Sample mean or proportion point estimates, with standard error and an approximate interval.
Open Point Estimate Calculator →SWP Calculator
See how long a systematic withdrawal plan lasts under an assumed return and yearly step-up.
Open SWP Calculator →Central Limit Theorem Calculator
Sampling distribution of the mean: standard error, z-scores and probabilities.
Open Central Limit Theorem Calculator →Pipe Volume Calculator
Internal volume and capacity of a pipe in litres and gallons from bore and length.
Open Pipe Volume Calculator →Combined Gas Law Calculator
Solve P1V1/T1 = P2V2/T2 for any one missing variable, with temperatures handled in Kelvin.
Open Combined Gas Law Calculator →Lottery Payout Calculator
Compare a lottery jackpot as an annuity versus a lump sum, after tax — clearly labelled as an estimate.
Open Lottery Payout Calculator →INR Calculator
Calculate INR from prothrombin time and ISI — a lab value to discuss with your clinician, never a self-dosing tool.
Open INR Calculator →Momentum Calculator
Solve p = mv for momentum, mass or velocity, with an impulse note for force over time.
Open Momentum Calculator →Walking Calorie Calculator
Estimate walking calories from weight, distance or steps, and pace, using MET values — an estimate, not a measurement.
Open Walking Calorie Calculator →Acreage Calculator
Turn length × width into acres, square feet, square metres and hectares in one step.
Open Acreage Calculator →Weight Loss Percentage Calculator
Turn start and current weight into a percentage lost, plus what remains to reach your goal.
Open Weight Loss Percentage Calculator →Rebar Calculator
Estimate rebar bars, total length and steel weight for a slab or footing from dimensions and spacing.
Open Rebar Calculator →BUN Creatinine Ratio Calculator
Divide BUN by creatinine for the ratio clinicians use to distinguish patterns of kidney stress — lab value only.
Open BUN Creatinine Ratio Calculator →Half Birthday Calculator
Find your half-birthday — six months after your birthday — and the next one coming up.
Open Half Birthday Calculator →Sand Calculator
Turn area × depth into sand volume, weight and bag count for gardens, patios and play areas.
Open Sand Calculator →Tarmac Calculator
Estimate asphalt tonnage for a driveway or road from area × depth, with wastage included.
Open Tarmac Calculator →Gram Schmidt Calculator
Turn 2–3 vectors into an orthonormal basis with the Gram–Schmidt steps shown.
Open Gram Schmidt Calculator →Anniversary Calculator
Count years, months and days since a special date, and find the next anniversary and its milestone name.
Open Anniversary Calculator →Free Fall Calculator
Find fall time, impact velocity or drop height, with gravity for Earth, the Moon or Mars — air resistance excluded.
Open Free Fall Calculator →Dog Pregnancy Calculator
From the mating date, estimate a dog’s due window around the typical 63-day gestation — vet confirmation advised.
Open Dog Pregnancy Calculator →Aquarium Calculator
Turn tank dimensions into water volume in litres and gallons, water weight, and a glass-thickness guide.
Open Aquarium Calculator →Perfect Square Trinomial Calculator
Check whether ax² + bx + c factors as a perfect square (px ± q)² — and see honestly why not, when it doesn’t.
Open Perfect Square Trinomial Calculator →Torque Calculator
Solve torque, force, lever arm or angle from τ = F × r × sin θ, with newton-metre, pound-foot and kilogram-force conversions.
Open Torque Calculator →Face Shape Calculator
Enter four face measurements to get an estimated face shape — oval, round, square, heart, oblong or diamond — with the runner-up shape shown.
Open Face Shape Calculator →Rotate PDF
Rotate PDF pages by 90°, 180° or 270° — all, odd, even or custom pages — entirely in your browser, with nothing uploaded.
Open Rotate PDF →Centroid Calculator
Find the centroid of any 2D point set or triangle, with the sums and steps shown so you can check the arithmetic.
Open Centroid Calculator →Dice Probability Calculator
Get the exact probability of any dice total — exact, at-least and at-most odds for NdS, counted exactly, not simulated.
Open Dice Probability Calculator →Strike Rate Calculator
Work out a batter strike rate from runs and balls faced — plus runs per over, boundary share and balls per boundary.
Open Strike Rate Calculator →Moment of Inertia Calculator
Moment of inertia for spheres, cylinders, rods and plates — with radius of gyration, angular momentum and rotational energy.
Open Moment of Inertia Calculator →2's Complement Calculator
Convert between binary and signed decimal with two's complement — plus one's complement, unsigned value and hex.
Open 2's Complement Calculator →Specific Heat Calculator
Solve any side of Q = mcΔT — specific heat, heat energy, mass or temperature change — in J, kJ, calories or kcal.
Open Specific Heat Calculator →Cat Age Calculator
Convert your cat age to human years — with life stage, next-birthday age and an estimate of remaining senior years.
Open Cat Age Calculator →Gravitational Force Calculator
Newton's law of universal gravitation — the force between any two masses, plus the acceleration each mass feels.
Open Gravitational Force Calculator →Grade Curve Calculator
Curve a grade three ways — bell curve, flat points or square-root curve — with letter grade and class percentile.
Open Grade Curve Calculator →YTM Calculator
Yield to maturity for any bond — annual and per-period yield, current yield, coupon income and total gain.
Open YTM Calculator →Titration Calculator
Solve titration problems — unknown concentration, unknown volume or moles reacted — with stoichiometric ratios.
Open Titration Calculator →Fiber Calculator
How much fiber you need each day — from age and sex, or from your calories — and how far your current intake falls short.
Open Fiber Calculator →Rational or Irrational Calculator
Is it rational or irrational? Test decimals, fractions, repeating decimals and square roots — with the reason why.
Open Rational or Irrational Calculator →Projectile Motion Calculator
Range, max height, flight time and impact speed for any launch — on Earth, the Moon, Mars or custom gravity.
Open Projectile Motion Calculator →Travel Time Calculator
How long a journey takes — from distance and speed or pace — with breaks, average speed and arrival time.
Open Travel Time Calculator →Gold Weight Calculator
Pure gold content of any item — convert grams, troy ounces, tolas and grains, and value it at your price per gram.
Open Gold Weight Calculator →Time Dilation Calculator
Einstein's time dilation — how much slower a moving clock runs, the Lorentz factor, and the time difference.
Open Time Dilation Calculator →Flooring Calculator
How many planks or tiles your floor needs — room area, waste allowance and material cost in one pass.
Open Flooring Calculator →Discriminant Calculator
The discriminant of any quadratic — root nature, both roots, vertex, and sum and product of roots.
Open Discriminant Calculator →KG to ML Converter
Convert kilograms to millilitres for any substance — water, milk, oil, honey, flour and more, with cups and fluid ounces.
Open KG to ML Converter →Reynolds Number Calculator
Is the flow laminar or turbulent? Reynolds number from velocity, size and viscosity, with critical velocities.
Open Reynolds Number Calculator →pH Calculator
pH from hydrogen or hydroxide concentration, from pOH, or for a weak acid — with pOH, both ion concentrations and acidity class.
Open pH Calculator →Expiry Calculator
Enter an expiry date and see exactly how many days are left, whether it has expired, and when to use the item first.
Open Expiry Calculator →Exponential Function Calculator
Evaluate a × b^x, find doubling and halving times, and solve exponential equations for x with growth and decay explained.
Open Exponential Function Calculator →Elasticity of Demand Calculator
Price, income and cross-price elasticity of demand by the midpoint method — elastic or inelastic, normal or inferior, substitute or complement.
Open Elasticity of Demand Calculator →Coterminal Angle Calculator
Find the coterminal angle between 0 and 360 degrees, its reference angle, quadrant and equivalent angles in degrees and radians.
Open Coterminal Angle Calculator →Basis Point Calculator
Convert basis points to percent and decimals, compare rate changes, and work out what a basis-point move costs on a loan or investment.
Open Basis Point Calculator →Framing Calculator
Wall framing quantities: studs, plates, headers and total lumber length from wall length, height, stud spacing and openings.
Open Framing Calculator →Center of Mass Calculator
The centre of mass of up to four point masses in a plane, with total mass, moments and distance from the origin.
Open Center of Mass Calculator →ACR Calculator
Albumin-creatinine ratio from urine albumin and creatinine, in mg/g and mg/mmol, with the standard kidney-health categories.
Open ACR Calculator →Direct Variation Calculator
Direct variation y = kx: find the constant of variation, or solve for x or y from any known pair.
Open Direct Variation Calculator →Base Calculator
Convert numbers between any bases from 2 to 36, with binary, octal, decimal and hexadecimal shown alongside.
Open Base Calculator →Z Test Calculator
One-sample z-test with a known population standard deviation: z-statistic, p-value, confidence interval and the reject-or-not decision.
Open Z Test Calculator →WACC Calculator
Weighted average cost of capital from equity, debt and optional preferred stock, with after-tax debt cost and capital weights.
Open WACC Calculator →Blood Type Calculator
Possible child blood types from the parents' blood types, with exact probabilities when a parent's genotype is known.
Open Blood Type Calculator →Marginal Revenue Calculator
Marginal revenue from a change in total revenue and quantity sold, with average revenue before and after and the revenue effect explained.
Open Marginal Revenue Calculator →Friction Calculator
Friction force from coefficient and normal force, or the full incline picture: normal force, sliding check and acceleration down a slope.
Open Friction Calculator →Geometric Series Calculator
Geometric sequences and series: nth term, finite sum, infinite sum when it converges, and the first terms listed.
Open Geometric Series Calculator →Add Watermark to PDF
Add a text watermark to any PDF entirely in your browser — position, size, colour, opacity and rotation, on all pages or a selection.
Open Add Watermark to PDF →PDF to XLS Converter
Extract text tables from a PDF into a genuine .xlsx spreadsheet in your browser — rows rebuilt from text positions, one sheet, ready for Excel.
Open PDF to XLS Converter →Opportunity Cost Calculator
Compare what you earn with your chosen option against the next-best alternative, and see exactly what that choice costs you over time.
Open Opportunity Cost Calculator →T Critical Value Calculator
Find the exact t critical value for any degrees of freedom, significance level and tail, and get the p-value for an observed t statistic.
Open T Critical Value Calculator →0-60 Calculator
Turn any 0-60 time into average acceleration, distance covered and g-force — or estimate a 0-60 time from power and weight.
Open 0-60 Calculator →Reciprocal Calculator
Find the reciprocal of any number or fraction — 1 divided by x — shown as a decimal, a simplified fraction and a percentage.
Open Reciprocal Calculator →Graduation By Birthday Calculator
Enter a birthday and a school-entry cutoff to find the expected kindergarten start, high-school graduation year and college graduation year.
Open Graduation By Birthday Calculator →Finance Charge Calculator
Work out the full finance charge on a credit card statement: interest under three balance methods, plus late, over-limit, cash-advance and other fees.
Open Finance Charge Calculator →Ideal Gas Law Calculator
Solve PV = nRT for any missing variable — pressure, volume, moles or temperature — with full unit conversion and an optional density result.
Open Ideal Gas Law Calculator →Binomial Coefficient Calculator
Compute C(n, k) exactly — 'n choose k' — plus the binomial probability of exactly k successes, with the full distribution table.
Open Binomial Coefficient Calculator →Boyle's Law Calculator
Solve Boyle's law P₁V₁ = P₂V₂ for any missing pressure or volume, with pressure and volume unit conversion built in.
Open Boyle's Law Calculator →Break Even Calculator
Find the break-even point for a product or business: how many units you must sell to cover fixed and variable costs, and the profit at any volume.
Open Break Even Calculator →What Year Was I Born If I Was 16 Calculator
Work out your birth year from the age you were in a given year — or find the year you turn any age from your birth year.
Open What Year Was I Born If I Was 16 Calculator →Polar Coordinates Calculator
Convert between polar (r, θ) and Cartesian (x, y) coordinates, with the angle in degrees or radians, the quadrant and the negative-r form.
Open Polar Coordinates Calculator →Rolle's Theorem Calculator
Check Rolle's theorem for a polynomial on an interval: verify f(a) = f(b), find every c with f′(c) = 0, and see whether the theorem applies.
Open Rolle's Theorem Calculator →KG to Gallons Converter
Convert kilograms (or pounds) to gallons: pick the substance — water, milk, oil, fuel, honey or your own density — because mass-to-volume depends on density.
Open KG to Gallons Converter →Charles Law Calculator
Solve Charles's law V₁/T₁ = V₂/T₂ at constant pressure — any one missing volume or temperature, in °C, °F or Kelvin.
Open Charles Law Calculator →Greater Than Less Than Calculator
Compare two numbers with >, < or = — plus the difference, ratio and percent difference.
Open Greater Than Less Than Calculator →River Rock Calculator
Work out how much river rock you need — volume, tons and bags — for a bed, path or border.
Open River Rock Calculator →Elimination Calculator
Solve two simultaneous equations by elimination, with the working and a substitution check.
Open Elimination Calculator →Set Builder Notation Calculator
Turn a list, interval or condition into proper set-builder notation — with roster form and a plain reading.
Open Set Builder Notation Calculator →Theoretical Yield Calculator
Find the maximum product mass from stoichiometry — plus percent yield when you enter what you actually made.
Open Theoretical Yield Calculator →Block Calculator
Count concrete blocks for a wall — area, exact count, waste-inclusive order and mortar bags.
Open Block Calculator →Home Appreciation Calculator
Project what a home could be worth — future value, total gain and equivalent monthly growth.
Open Home Appreciation Calculator →Orthocenter Calculator
Find where a triangle's three altitudes meet — with the triangle type and inside/outside position.
Open Orthocenter Calculator →PDF to Excel Converter
Convert a text-based PDF's tables into a genuine .xlsx spreadsheet in your browser — nothing uploaded.
Open PDF to Excel Converter →Earnings Per Share Calculator
Basic and diluted EPS from net income, preferred dividends and share count — with a loss warning.
Open Earnings Per Share Calculator →Cash Back Calculator
Estimate monthly and annual cash back — with a bonus-category rate and your true effective rate.
Open Cash Back Calculator →Sonotube Concrete Calculator
Concrete volume and bag count for round Sonotube forms — by tube size, height and bag size, with waste and cost.
Open Sonotube Concrete Calculator →Glass Weight Calculator
Weight of a glass pane, round disc or tube from its size, thickness and glass type — in kg and pounds.
Open Glass Weight Calculator →Price Per Square Foot Calculator
Price per square foot from total price and area — or total price, affordable area, and a two-property comparison.
Open Price Per Square Foot Calculator →Image to PNG Converter
Convert JPG, PNG, WebP, SVG, BMP and GIF pictures to PNG in your browser — with transparency and size options.
Open Image to PNG Converter →HEIC to PNG Converter
Turn iPhone HEIC photos into lossless PNGs in your browser — decoded with libheif, so it works in any browser.
Open HEIC to PNG Converter →Appreciation Calculator
Future value of any asset growing (or falling) by a yearly percentage — with inflation-adjusted value and doubling time.
Open Appreciation Calculator →FB2 to EPUB Converter
Convert FB2 e-books to genuine EPUB files in your browser — text and chapter structure preserved, nothing uploaded.
Open FB2 to EPUB Converter →JPG to ICO Converter
Turn JPG pictures into genuine Windows ICO icon files in your browser — 16, 32, 48 and optional 256 px sizes.
Open JPG to ICO Converter →TXT to PDF Converter
Convert plain-text files to real, selectable PDFs in your browser — A4 or Letter, with headers and page numbers.
Open TXT to PDF Converter →CM to Feet Converter
Convert centimetres to feet — with inches, metres and feet+inches shown together.
Open CM to Feet Converter →Meters to Feet Converter
Convert metres to feet — with inches, centimetres and feet+inches shown together.
Open Meters to Feet Converter →Inches to Feet Converter
Convert inches to feet — with centimetres, metres and feet+inches shown together.
Open Inches to Feet Converter →Temperature Converter
Convert Celsius, Fahrenheit, Kelvin and Rankine — with everyday reference points.
Open Temperature Converter →Ounces to Pounds Converter
Convert ounces to pounds — with grams, kilograms and pounds+ounces shown together.
Open Ounces to Pounds Converter →Ounces to Gallons Converter
Convert fluid ounces to gallons — US and UK gallons, litres and cups shown together.
Open Ounces to Gallons Converter →Grams to Pounds Converter
Convert grams to pounds — with ounces, kilograms and pounds+ounces shown together.
Open Grams to Pounds Converter →Ounces to Grams Converter
Convert ounces to grams — with kilograms, pounds and pounds+ounces shown together.
Open Ounces to Grams Converter →Grams to Cups Converter
Convert grams to cups for real ingredients — flour, sugar, butter, honey and more, each with its own density.
Open Grams to Cups Converter →Ounces to Liters Converter
Convert fluid ounces to litres — with millilitres, gallons and cups shown together.
Open Ounces to Liters Converter →Teaspoons to Tablespoons Converter
Convert teaspoons to tablespoons — with millilitres, cups and fluid ounces shown together.
Open Teaspoons to Tablespoons Converter →Liters to Ounces Converter
Convert litres to fluid ounces — with millilitres, gallons and cups shown together.
Open Liters to Ounces Converter →Pounds to Ounces Converter
Convert pounds to ounces — with grams, kilograms and pounds+ounces shown together.
Open Pounds to Ounces Converter →Square Feet to Acres Converter
Convert square feet to acres — with square metres, hectares and square yards shown together.
Open Square Feet to Acres Converter →Tablespoons to Cups Converter
Convert tablespoons to cups — with millilitres, fluid ounces and teaspoons shown together.
Open Tablespoons to Cups Converter →KPH to MPH Converter
Convert km/h to mph — with metres per second, knots and feet per second shown together.
Open KPH to MPH Converter →Cups to Grams Converter
Convert cups to grams for real ingredients — flour, sugar, butter, honey and more, each with its own density.
Open Cups to Grams Converter →Meters to Inches Converter
Convert metres to inches — with feet, centimetres and feet+inches shown together.
Open Meters to Inches Converter →Cups to ML Converter
Convert cups to millilitres — with litres, fluid ounces and tablespoons shown together.
Open Cups to ML Converter →ML to Liters Converter
Convert millilitres to litres — with fluid ounces, cups and gallons shown together.
Open ML to Liters Converter →Liters to ML Converter
Convert litres to millilitres — with fluid ounces, cups and gallons shown together.
Open Liters to ML Converter →Acres to Square Feet Converter
Convert acres to square feet — with square metres, hectares and square yards shown together.
Open Acres to Square Feet Converter →Grams to Tablespoons Converter
Convert grams to tablespoons for real ingredients — butter, flour, sugar, honey and more.
Open Grams to Tablespoons Converter →Hectares to Acres Converter
Convert hectares to acres (and back) — with the full area family, from square metres to square miles.
Open Hectares to Acres Converter →MG to Grams Converter
Convert milligrams to grams (and back) — with the full weight family, from milligrams to tonnes.
Open MG to Grams Converter →Gallons to Ounces Converter
Convert gallons to fluid ounces (and back) — US or Imperial gallons, with the full volume family.
Open Gallons to Ounces Converter →Grams to Teaspoons Converter
Convert grams to teaspoons (and back) — pick your ingredient, because grams-to-spoons depends on density. Water, flour, sugar, honey and more included.
Open Grams to Teaspoons Converter →Tablespoons to Grams Converter
Convert tablespoons to grams (and back) — pick your ingredient, because a tablespoon's weight depends on density.
Open Tablespoons to Grams Converter →Teaspoons to Grams Converter
Convert teaspoons to grams (and back) — pick your ingredient, because a teaspoon's weight depends on density.
Open Teaspoons to Grams Converter →Cups to Pints Converter
Convert cups to pints (and back) — US or Imperial, with the full volume family for cooking and drinks.
Open Cups to Pints Converter →Gallons to Liters Converter
Convert gallons to litres (and back) — US or Imperial gallons, with the full volume family.
Open Gallons to Liters Converter →Miles to Feet Converter
Convert miles to feet (and back) — with the full length family, from millimetres to kilometres.
Open Miles to Feet Converter →Grams to MG Converter
Convert grams to milligrams (and back) — with the full weight family, from milligrams to tonnes.
Open Grams to MG Converter →Teaspoons to ML Converter
Convert teaspoons to millilitres (and back) — plus the weight in grams for your chosen ingredient.
Open Teaspoons to ML Converter →Cups to Tablespoons Converter
Convert cups to tablespoons (and back) — US or Imperial cups, with the full volume family.
Open Cups to Tablespoons Converter →ML to Teaspoons Converter
Convert millilitres to teaspoons (and back) — plus the weight in grams for your chosen ingredient.
Open ML to Teaspoons Converter →Pints to Ounces Converter
Convert pints to fluid ounces (and back) — US or Imperial pints, with the full volume family.
Open Pints to Ounces Converter →Tablespoons to Teaspoons Converter
Convert tablespoons to teaspoons (and back) — with the full volume family for scaling recipes.
Open Tablespoons to Teaspoons Converter →Ounces to KG Converter
Convert ounces to kilograms (and back) — with the full weight family, including stone and all three tons.
Open Ounces to KG Converter →Tons to Pounds Converter
Convert tons to pounds (and back) — US short tons, UK long tons and metric tonnes, clearly labelled, with the full weight family.
Open Tons to Pounds Converter →Acres to Hectares Converter
Convert acres to hectares (and back) — with the full area family, from square metres to square miles.
Open Acres to Hectares Converter →Hours to Seconds Converter
Convert hours to seconds (and back) — with the full time family, from milliseconds to weeks.
Open Hours to Seconds Converter →Meters to CM Converter
Convert metres to centimetres (and back) — with the full length family, from millimetres to miles.
Open Meters to CM Converter →Inches to MM Converter
Convert inches to millimetres (and back) — exact, with feet+inches style results and the full length family.
Open Inches to MM Converter →Days to Years Converter
Convert days to years (and back) — leap-year aware, with weeks and months, and the calendar-day range for any span of years.
Open Days to Years Converter →PDF Editor
Edit PDFs in your browser — add text, rotate, delete and reorder pages, and fill real form fields, all without uploading a thing.
Open PDF Editor →Crop PDF
Crop PDF pages to any region you choose — drag on the preview or type exact percentages, for all pages or just some.
Open Crop PDF →OCR PDF
Turn scanned and image-only PDFs back into searchable, copyable text — read entirely in your browser, nothing uploaded.
Open OCR PDF →Sign PDF
Sign any PDF in your browser — draw, type or upload your signature, place it on any page, and download the signed file.
Open Sign PDF →JPG to Excel Converter
Turn a photo of a table into a real Excel spreadsheet — OCR reads the table in your browser and exports a genuine .xlsx or CSV.
Open JPG to Excel Converter →Document Scanner
Scan documents with your camera or upload images — rotate, enhance and save as a multi-page PDF, right in your browser.
Open Document Scanner →Remove Watermark from PDF
Remove a text watermark from your PDF in your browser — image watermarks cannot be reliably removed in-browser and are left untouched.
Open Remove Watermark from PDF →Image Background Remover
Remove the background from a photo in your browser — flood-fill from the edges, with tolerance and feathered edges, exported as a transparent PNG.
Open Image Background Remover →PDF to PDF/A Converter
Convert a PDF toward PDF/A archival format in your browser — best-effort PDF/A-2b output with XMP identification and an sRGB OutputIntent. Validate with veraPDF for certified archival use.
Open PDF to PDF/A Converter →HTML to PDF Converter
Convert structured HTML into a clean, styled PDF in your browser — headings, paragraphs, lists, links and basic tables. Complex CSS layouts are not preserved.
Open HTML to PDF Converter →Compare PDF
Compare two PDFs line by line in your browser — see exactly what was added, removed or kept, side by side. Scanned PDFs without a text layer cannot be compared.
Open Compare PDF →Image to Text Converter
Copy text from any image — upload a photo or screenshot and read its printed English text in your browser, nothing uploaded.
Open Image to Text Converter →Word to Excel Converter
Convert Word documents to Excel spreadsheets in your browser — tables become rows, paragraphs become single-column rows. Formatting is not carried over.
Open Word to Excel Converter →Add Page Numbers to PDF
Add page numbers to any PDF in your browser — choose position, format and starting number. Original content is unchanged.
Open Add Page Numbers to PDF →Excel to Word Converter
Convert Excel spreadsheets to Word documents in your browser — rows become a Word table. Formulas export as stored values.
Open Excel to Word Converter →PowerPoint to Word Converter
Convert PowerPoint presentations to Word documents in your browser — each slide becomes a headed section. Designs and images are not carried over.
Open PowerPoint to Word Converter →PDF to EPUB Converter
Convert a PDF to a reflowable EPUB ebook in your browser — text only, in reading order. Original layout, fonts and images are not preserved.
Open PDF to EPUB Converter →PDF to Text Converter
Convert PDF to plain text in your browser — every page extracted in order, with page markers. Scanned PDFs cannot be converted.
Open PDF to Text Converter →PDF to XML Converter
Convert PDF to structured XML in your browser — one <page> element per page, one <line> per text line. Scanned PDFs cannot be converted.
Open PDF to XML Converter →PDF to ODT Converter
Convert PDF to an editable ODT document in your browser — text only, in reading order, for LibreOffice or Word. Layout and images are not preserved.
Open PDF to ODT Converter →JSON Formatter
Validate, pretty-print and minify JSON in your browser — with error positions, sorted keys and size stats.
Open JSON Formatter →Hash Generator
Generate SHA-256, SHA-1 and MD5 hashes of any text, entirely in your browser — nothing is uploaded.
Open Hash Generator →Base64 Encoder / Decoder
Encode and decode Base64 with full Unicode (UTF-8) support, plus URL-safe Base64 for tokens and URLs.
Open Base64 Encoder / Decoder →URL Encoder / Decoder
Percent-encode and decode URLs — component, full-URL and form (application/x-www-form-urlencoded) modes.
Open URL Encoder / Decoder →URL Parser
Break any URL into protocol, host, port, path, query parameters and fragment — and rebuild it.
Open URL Parser →JWT Decoder / Debugger
Decode a JWT header and payload, check its expiry, and see whether a signature is present — without ever sending your token anywhere.
Open JWT Decoder / Debugger →Regex Tester
Test regular expressions live: highlighted matches, capture groups and a replace preview, with warnings for risky patterns.
Open Regex Tester →API Key Generator
Generate cryptographically random API keys — any length, charset and prefix, with an entropy rating. Never Math.random.
Open API Key Generator →SQL Generator
Build SELECT queries with filters, joins and sorting, or CREATE TABLE statements — with identifiers and values safely escaped.
Open SQL Generator →SQL INSERT Generator
Turn pasted CSV or JSON rows into bulk INSERT statements — with escaping, batching and MySQL / PostgreSQL dialects.
Open SQL INSERT Generator →XML Formatter
Validate, pretty-print and minify XML — with real nesting, attributes, CDATA, comments and mismatched-tag errors.
Open XML Formatter →Cron Expression Generator
Build cron expressions visually, read them in plain English, and see the next 5 run times.
Open Cron Expression Generator →Meta Tag Generator
Generate copy-ready SEO and social meta tags — title, description, canonical, Open Graph and Twitter — with completeness checks.
Open Meta Tag Generator →Robots.txt Generator
Generate a valid robots.txt — user-agents, Allow/Disallow rules, crawl-delay and sitemaps — with syntax warnings.
Open Robots.txt Generator →Security Headers Generator
Build Content-Security-Policy, CORS and Permissions-Policy headers from presets, with validation warnings.
Open Security Headers Generator →Chmod Calculator
Convert between numeric (755) and symbolic (rwxr-xr-x) file permissions — including setuid, setgid and sticky bits.
Open Chmod Calculator →Markdown Preview
Write Markdown and see a live preview — headings, lists, tables, code and links, rendered instantly in your browser.
Open Markdown Preview →Diff Checker
Compare two texts line by line — see exactly what was added, removed or left unchanged, with a clear summary.
Open Diff Checker →YAML to JSON Converter
Convert YAML to JSON in your browser — block mappings, sequences and scalars, with clear errors for unsupported YAML.
Open YAML to JSON Converter →CSV to JSON Converter
Convert CSV to JSON — with proper quoted fields, embedded commas and line breaks handled correctly.
Open CSV to JSON Converter →HTML Entity Encoder
Encode text into safe HTML entities — or decode entities back to plain text — with named and numeric entities.
Open HTML Entity Encoder →Text Encryption Tool
Encrypt text in your browser with AES-GCM — nothing is uploaded, and only your password can unlock it again.
Open Text Encryption Tool →JSON Schema Generator
Paste JSON and get a ready-to-use JSON Schema — types, required fields, nested objects and arrays inferred automatically.
Open JSON Schema Generator →TypeScript Interface Generator
Turn JSON into clean TypeScript interfaces — nested types, arrays and optional fields handled automatically.
Open TypeScript Interface Generator →Bcrypt Generator
Hash a password with bcrypt in your browser — pick the cost, verify a hash, and never send the password anywhere.
Open Bcrypt Generator →SPF Record Generator
Build a valid SPF record for your domain — with the 10-DNS-lookup limit checked before you publish.
Open SPF Record Generator →DMARC Record Generator
Build a DMARC record — policy, reporting addresses and alignment — with plain-English guidance.
Open DMARC Record Generator →DKIM Record Generator
Generate a DKIM key pair in your browser and get the DNS record — private key stays with you, never uploaded.
Open DKIM Record Generator →User Agent Generator
Build realistic browser user-agent strings — pick browser, OS and device, copy the string, and test with it.
Open User Agent Generator →Password Strength Checker
Check how strong a password is — entropy, common-password and pattern checks — with honest, practical advice.
Open Password Strength Checker →TOTP Generator
Generate time-based one-time codes (TOTP) from your secret — live ticking code, countdown and manual setup details.
Open TOTP Generator →Bulk CSV Generator
Generate bulk CSV rows for testing — names, emails, numbers, dates and custom lists, all safe generic data.
Open Bulk CSV Generator →Mock API Generator
Design mock REST API endpoints and get instant sample JSON responses for front-end development and testing.
Open Mock API Generator →Markdown to HTML Converter
Convert Markdown to clean HTML instantly — headings, lists, links, code blocks and tables, with safe escaping.
Open Markdown to HTML Converter →GraphQL Query Builder
Build GraphQL queries and mutations visually — pick fields and arguments, get a copy-ready query string.
Open GraphQL Query Builder →Env File Generator
Generate a clean .env file for your project — database, app, mail and custom variables with safe quoting.
Open Env File Generator →HTTP Error Response Generator
Generate standard API error responses in JSON — RFC 7807 problem details, simple messages and Express-style errors.
Open HTTP Error Response Generator →UUID Generator
Generate random UUIDs (v4 and time-ordered variants) for database keys, test data and distributed systems.
Open UUID Generator →ULID Generator
Generate sortable ULIDs — 26-character Crockford base32 IDs with a millisecond timestamp prefix.
Open ULID Generator →Docker Compose Generator
Build a Docker Compose file visually — services, images, ports, volumes and environment variables.
Open Docker Compose Generator →Gitignore Generator
Generate a .gitignore file from templates for your stack, plus your own custom ignore patterns.
Open Gitignore Generator →SQL to MongoDB Converter
Convert basic SQL SELECT queries into MongoDB find() calls — filters, sorting and limits.
Open SQL to MongoDB Converter →Kubernetes YAML Generator
Generate Kubernetes Deployment and Service YAML — replicas, images, ports and resource limits.
Open Kubernetes YAML Generator →NGINX Config Generator
Build NGINX server blocks — reverse proxy, static sites, redirects and SSL placeholders.
Open NGINX Config Generator →Htpasswd Generator
Generate Apache htpasswd entries with bcrypt or SHA-1 hashes — passwords never leave your browser.
Open Htpasswd Generator →CSP Generator
Build a Content-Security-Policy header from directive pickers — protect your site from XSS and injection.
Open CSP Generator →CORS Generator
Generate CORS headers — allowed origins, methods and headers, with credential warnings built in.
Open CORS Generator →Permissions Policy Generator
Build a Permissions-Policy header to control camera, microphone, geolocation and other browser features.
Open Permissions Policy Generator →Editorconfig Generator
Generate an .editorconfig file — consistent indentation, line endings and charset across editors.
Open Editorconfig Generator →Prettier Config Generator
Create a Prettier configuration — print width, tabs, quotes, semicolons and trailing commas.
Open Prettier Config Generator →Vite Config Generator
Generate a Vite config file — plugins, server port, base path, build options and sourcemaps.
Open Vite Config Generator →ESLint Config Generator
Create an ESLint configuration — flat (ESLint 9) or legacy .eslintrc, with style rules you choose.
Open ESLint Config Generator →Tsconfig Generator
Build a TypeScript tsconfig.json — strictness, target, module system and path aliases.
Open Tsconfig Generator →Drizzle Schema Generator
Generate Drizzle ORM table schemas from your field list — types, defaults and constraints.
Open Drizzle Schema Generator →Prisma Schema Generator
Generate a Prisma schema — models, fields, relations and database provider, ready to paste.
Open Prisma Schema Generator →GitHub Actions Generator
Build a GitHub Actions workflow YAML — triggers, jobs and steps for Node, Python or deploy flows.
Open GitHub Actions Generator →Htaccess Generator
Generate Apache .htaccess rules — redirects, rewrites, HTTPS forcing, caching and access control.
Open Htaccess Generator →JSON Validator
Validate JSON instantly with precise error positions, then pretty-print or minify it.
Open JSON Validator →Luhn Checker
Check any card-style number with the Luhn algorithm and identify its brand by prefix — validation only.
Open Luhn Checker →Phone Validator
Validate phone numbers by country format and E.164 rules — format checks only, nothing generated.
Open Phone Validator →Crypto Address Validator
Validate Bitcoin and Ethereum addresses — Base58Check, Bech32/Bech32m checksums and ETH format checks.
Open Crypto Address Validator →BIN Checker
Check a card BIN format, Luhn validity and brand by prefix — no live BIN database, bank not identified.
Open BIN Checker →Crypto Address Generator
Generate random test-only crypto addresses for development — never use with real funds.
Open Crypto Address Generator →ISBN Generator
Generate valid ISBN-13 and ISBN-10 numbers with correct check digits, or validate an existing ISBN.
Open ISBN Generator →VCard Generator
Create a vCard contact file (.vcf) — name, phone, email, organisation and address, ready to download.
Open VCard Generator →Serial Number Generator
Generate pattern-based serial numbers for testing and inventory demos — samples only, not manufacturer serials.
Open Serial Number Generator →Tracking Number Generator
Generate carrier-format tracking number samples for testing — format samples only, not real shipments.
Open Tracking Number Generator →Geo Coordinates Generator
Generate sample latitude/longitude coordinates around real city centres for testing maps and apps.
Open Geo Coordinates Generator →Nonce Generator
Generate cryptographically random nonces in hex or base64 for CSP headers, auth flows and testing.
Open Nonce Generator →PKCE Generator
Generate a PKCE code verifier and S256 code challenge for OAuth 2.0 authorisation flows.
Open PKCE Generator →HMAC Generator
Compute HMAC signatures with SHA-1, SHA-256, SHA-384 or SHA-512 — hex and base64 output.
Open HMAC Generator →SRI Hash Generator
Generate Subresource Integrity hashes (SHA-256/384/512) for scripts and stylesheets you host.
Open SRI Hash Generator →Color Generator
Generate random colours and harmonious palettes — complementary, triadic, analogous and more, click to copy.
Open Color Generator →Color Converter
Convert colours between hex, RGB, HSL, HSV and CMYK — with alpha support and instant previews.
Open Color Converter →Gradient Generator
Build CSS gradients — linear or radial, multi-stop, with live preview and copy-ready code.
Open Gradient Generator →Hex Color Generator
Generate random hex colours with light, dark, pastel and vivid filters, plus a copy history.
Open Hex Color Generator →CSS Box Shadow Generator
Design CSS box shadows with layered controls — offset, blur, spread, colour and inset, live preview.
Open CSS Box Shadow Generator →Lorem Ipsum Generator
Generate Lorem Ipsum placeholder text by paragraphs, sentences or words for layouts and mockups.
Open Lorem Ipsum Generator →Slug Generator
Turn any title into a clean URL slug — separators, stop-word removal and length limits included.
Open Slug Generator →Contrast Checker
Check text/background colour contrast against WCAG AA and AAA — exact ratio and pass/fail verdicts.
Open Contrast Checker →Case Converter
Convert text between camelCase, PascalCase, snake_case, kebab-case, Title Case and more in one go.
Open Case Converter →Chart Generator
Turn pasted CSV data into bar, line or pie charts on canvas — customise colours and download PNG.
Open Chart Generator →Unix Timestamp Converter
Convert Unix timestamps (seconds and milliseconds) to human dates and back, in UTC and local time.
Open Unix Timestamp Converter →Timezone Converter
Convert a time between time zones with DST handled — pick explicit zones, never host-timezone guesses.
Open Timezone Converter →Image to Base64 Converter
Convert an image to a base64 data URI — drag, drop, copy the code or download it as text.
Open Image to Base64 Converter →Aspect Ratio Calculator
Work out aspect ratios and scaled resolutions — presets like 16:9 plus custom width/height maths.
Open Aspect Ratio Calculator →Placeholder Image Generator
Generate custom placeholder images — any size, text and colours, downloaded as PNG.
Open Placeholder Image Generator →Color Blindness Simulator
Simulate how an image looks with protanopia, deuteranopia, tritanopia and other colour vision types.
Open Color Blindness Simulator →QR Code Generator
Generate QR codes with error-correction levels, colours and sizes — download as PNG or SVG.
Open QR Code Generator →Meme Generator
Make memes in your browser — upload an image, add top and bottom text, download the result.
Open Meme Generator →Signature Pad
Draw your signature with mouse or touch and download it as a transparent or white-background PNG.
Open Signature Pad →Barcode Generator
Generate Code128 barcodes from any text — with checksum, human-readable text and SVG/PNG download.
Open Barcode Generator →Invoice Number Generator
Generate invoice numbers from your pattern — prefix, date parts and padded sequences, with previews.
Open Invoice Number Generator →PO Number Generator
Generate purchase order numbers from your pattern — prefix, date parts and padded sequences.
Open PO Number Generator →Username Generator
Generate username ideas from word lists with length and separator filters — suggestions only.
Open Username Generator →Quote Generator
Get random quotes by category — motivational, success, life and funny — with one-click copy.
Open Quote Generator →Angle Converter
Convert angles between degrees, radians, gradians, turns and arcminutes/arcseconds.
Open Angle Converter →BTU to Tons and kW Converter
Convert cooling capacity between BTU/h, refrigeration tons and kilowatts.
Open BTU to Tons and kW Converter →Data Size Converter
Convert data sizes between bits, bytes, KB/MB/GB and KiB/MiB/GiB — binary and decimal labelled clearly.
Open Data Size Converter →dBm to Watts Converter
Convert dBm to milliwatts, watts and microwatts for RF and signal power work.
Open dBm to Watts Converter →Fuel Economy Converter
Convert fuel economy between US mpg, UK mpg, L/100 km and km/L — reciprocal scale handled correctly.
Open Fuel Economy Converter →Fuel Price Converter
Convert fuel prices between per litre, per US gallon and per UK gallon, in any currency.
Open Fuel Price Converter →Cholesterol Unit Converter
Convert cholesterol and triglycerides between mg/dL and mmol/L, with lipid-panel interpretation.
Open Cholesterol Unit Converter →Coins to Dollars Converter
Turn coin counts into dollars — US coins with a breakdown, plus a fewest-coins change mode.
Open Coins to Dollars Converter →Cooking Measurement Converter
Convert kitchen measures for real ingredients — cups, spoons and millilitres to grams and ounces.
Open Cooking Measurement Converter →Cups to Pounds Converter
Convert cups to pounds for common baking ingredients using standard densities — the quick pair converter.
Open Cups to Pounds Converter →Coordinates Converter
Convert coordinates between decimal degrees, DMS and DMM — plus verified UTM conversion.
Open Coordinates Converter →Data Transfer Converter
Convert data transfer rates between bps, Kbps, Mbps and B/s — plus a download-time estimator.
Open Data Transfer Converter →Drops to ML Converter
Convert drops to millilitres with an adjustable drops-per-ml rate — drop size varies, so it stays honest.
Open Drops to ML Converter →Engine Hours to Miles Converter
Convert engine hours to miles with an explicit average-speed input — the assumption is never hidden.
Open Engine Hours to Miles Converter →Fresh to Dry Herb Converter
Convert fresh herbs to dried (and bunches) at the standard 3:1 ratio across 12 common herbs.
Open Fresh to Dry Herb Converter →Gauge Pressure Converter
Convert gauge pressure (psig) to absolute pressure (psia) and bar/kPa — atmosphere adjustable.
Open Gauge Pressure Converter →Hardness Converter
Convert hardness between Rockwell, Brinell, Vickers and Knoop scales — steel approximations, clearly labelled.
Open Hardness Converter →Inches to Fraction Converter
Convert decimal inches to the nearest fraction (down to 1/64) with the rounding error shown.
Open Inches to Fraction Converter →Indian Land Unit Converter
Convert Indian land units — acre, hectare, bigha, katha, cent, guntha — with state variants labelled.
Open Indian Land Unit Converter →Internet Speed Converter
Convert internet speeds between Mbps, MB/s and more — bits vs bytes explained, plus download times.
Open Internet Speed Converter →Large Number Converter
Convert between Indian (lakh, crore, arab) and international (million, billion) number systems.
Open Large Number Converter →Lumens to Watts Converter
Estimate watts from lumens using bulb-type efficacy presets — an estimate, clearly labelled.
Open Lumens to Watts Converter →mcg to IU Converter
Convert micrograms to IU by substance — Vitamin D, A and E each get their own verified factor.
Open mcg to IU Converter →Mesh to Micron Converter
Convert sieve mesh numbers to microns from the standard approximate table.
Open Mesh to Micron Converter →Mil to Micron Converter
Convert mils (thousandths of an inch) to microns, millimetres and inches — 1 mil = 25.4 µm exactly.
Open Mil to Micron Converter →Minutes to Decimal Converter
Convert minutes to decimal hours for timesheets, with payroll rounding options.
Open Minutes to Decimal Converter →ML to Grams Converter
Convert millilitres to grams by ingredient density — water, milk, oil, honey, flour and more.
Open ML to Grams Converter →mmol/L to mg/dL Converter
Convert lab units between mmol/L and mg/dL for glucose, cholesterol, triglycerides and more.
Open mmol/L to mg/dL Converter →Natural Gas Converter
Convert natural gas between cubic metres, kWh, therms and BTU with an adjustable calorific value.
Open Natural Gas Converter →Nautical Mile Converter
Convert nautical miles and knots to kilometres, miles and km/h for marine and aviation use.
Open Nautical Mile Converter →Paper Quantity Converter
Convert paper quantities between sheets, quires, reams and bundles.
Open Paper Quantity Converter →Pixel Unit Converter
Convert pixels to inches, centimetres and points at any DPI — plus a screen PPI helper.
Open Pixel Unit Converter →Pounds to Cups Converter
Convert pounds to cups for common baking ingredients using standard densities.
Open Pounds to Cups Converter →PPM Converter
Convert ppm to mg/L, percent and ppb — plus a C1V1 = C2V2 dilution calculator.
Open PPM Converter →Rain to Snow Converter
Convert liquid precipitation to snow depth at an adjustable snow-to-liquid ratio (default 10:1).
Open Rain to Snow Converter →RF Unit Converter
Convert radio frequencies, find the wavelength, and identify the radio band — from LF to EHF.
Open RF Unit Converter →Scale Converter
Convert between real-world sizes and scale-model or map drawings at any ratio, in any length unit.
Open Scale Converter →Shoe Size Converter
Convert shoe sizes between US, UK and EU sizing using foot length — with the honest warning that brands vary.
Open Shoe Size Converter →Sodium in Salt Converter
Convert between salt (sodium chloride) and sodium — the number on nutrition labels is sodium, not salt.
Open Sodium in Salt Converter →Time to Decimal Converter
Convert hours:minutes:seconds to decimal hours and minutes — the format payroll and timesheets actually want.
Open Time to Decimal Converter →Torque to Horsepower Converter
Convert engine torque and RPM into horsepower (and kilowatts) — the curve that explains why torque and power cross at 5,252 RPM.
Open Torque to Horsepower Converter →Weird Units Converter
Convert delightfully odd historical and humorous units — furlongs, smoots, barns and more — into metres and everyday sizes.
Open Weird Units Converter →Wizarding Currency Converter
Convert Galleons, Sickles and Knuts — the wizarding currency of Harry Potter — with an unofficial Muggle-money estimate.
Open Wizarding Currency Converter →Age on Other Planets Calculator
How old would you be on Mercury, Venus, Mars and beyond? Divide your Earth age by each planet's year length.
Open Age on Other Planets Calculator →BC to AD Converter
Convert BC/BCE years to astronomical year numbering — and get the year gap right, remembering there is no year 0.
Open BC to AD Converter →Book Challenge Calculator
Plan a reading challenge: books per week, pages per day, and whether your goal fits your real reading time.
Open Book Challenge Calculator →Business Days Calculator
Count business days between two dates, excluding weekends and your own holiday list — or add N business days to a date.
Open Business Days Calculator →Countdown Calculator
A live countdown to any date and time in your local time zone — with the total in days, hours, minutes and seconds.
Open Countdown Calculator →Easter Date Calculator
Find Easter Sunday for any year with the Anonymous Gregorian Computus — plus Good Friday and Easter Monday.
Open Easter Date Calculator →Holiday Countdown Calculator
Days until Christmas, New Year, Halloween, Valentine's Day and more — from any date you choose.
Open Holiday Countdown Calculator →Korean Age Calculator
Traditional Korean age vs international age — and what changed with South Korea's June 2023 law.
Open Korean Age Calculator →Leap Year Checker
Is it a leap year? The Gregorian rule in one check — divisible by 4, except centuries, except multiples of 400.
Open Leap Year Checker →Lunar Age Calculator
Your lunar (traditional Chinese) age: 1 at birth, increasing at each Lunar New Year — usually 1–2 years above international age.
Open Lunar Age Calculator →Mayan Calendar Converter
Convert a Gregorian date to the Maya Long Count (baktun.katun.tun.uinal.kin) using the GMT correlation.
Open Mayan Calendar Converter →Military Time Converter
Convert between 12-hour (AM/PM) and 24-hour military time — with the midnight and noon traps explained.
Open Military Time Converter →Moon Phase Calculator
Find the Moon's phase, age and illumination for any date — from the synodic month of 29.53 days.
Open Moon Phase Calculator →Movie & TV Marathon Calculator
Plan a movie or TV marathon: total runtime, how many days it takes at your daily viewing hours, and what to watch when.
Open Movie & TV Marathon Calculator →Palindrome Date Checker
Is a date a palindrome? Check it in MMDDYYYY, DDMMYYYY, YYYYMMDD and more — and find the next one.
Open Palindrome Date Checker →Pomodoro Timer
Plan and run Pomodoro sessions: focused work intervals, short breaks, and a long break every fourth Pomodoro.
Open Pomodoro Timer →School Age Calculator
How old will your child be on the school cut-off date — and which school year does that usually mean?
Open School Age Calculator →Screen Time Alternatives Calculator
What could you do with the hours you spend scrolling? Turn daily screen time into books, walks, workouts and skills.
Open Screen Time Alternatives Calculator →Sidereal Time Calculator
Greenwich Mean Sidereal Time and Local Sidereal Time for any UTC date/time and longitude — the clock astronomers use.
Open Sidereal Time Calculator →28/36 Rule Calculator
Check housing and total debt against the 28% and 36% US mortgage underwriting caps.
Open 28/36 Rule Calculator →3X Rent Affordability Calculator
Check whether your income passes the 3× rent screen — and the highest rent that passes.
Open 3X Rent Affordability Calculator →403(b) Calculator
US 403(b) growth projection — your contributions, employer money and returns, year by year.
Open 403(b) Calculator →50/30/20 Budget Calculator
Split after-tax income into needs, wants and savings — and see where your actual spending differs.
Open 50/30/20 Budget Calculator →529 Plan Calculator
US 529 college savings projection — contributions, growth, and the future cost of college.
Open 529 Plan Calculator →Adjustable-Rate Mortgage Calculator
ARM payments now, at the first adjustment, and at the lifetime cap — with caps applied.
Open Adjustable-Rate Mortgage Calculator →Adjusted Gross Income Calculator
US adjusted gross income from total income minus above-the-line adjustments.
Open Adjusted Gross Income Calculator →After Repair Value Calculator
ARV profit, ROI and the 70% rule maximum offer for a flip or renovation deal.
Open After Repair Value Calculator →Alternative Minimum Tax Calculator
US federal AMT estimate — tentative minimum tax versus regular tax, with editable 2025 figures.
Open Alternative Minimum Tax Calculator →Altman Z-Score Calculator
Altman Z-score for public manufacturers — the original 1968 model, with all five ratios.
Open Altman Z-Score Calculator →Appliance Depreciation Calculator
Depreciate an appliance by straight-line or double-declining balance, with a full schedule.
Open Appliance Depreciation Calculator →Atal Pension Yojana Calculator
India APY estimate — pension slab, entry-age contribution and total paid to age 60 (indicative).
Open Atal Pension Yojana Calculator →Balance Transfer Calculator
Balance-transfer saving versus staying — intro period, fee and post-intro rate included.
Open Balance Transfer Calculator →Balloon Payment Calculator
Monthly payment and the lump-sum balloon due when a loan matures early.
Open Balloon Payment Calculator →Beach Price Index Calculator
Build your own beach-day price index from a five-item basket against any base.
Open Beach Price Index Calculator →Beta Calculator
Beta from covariance and market variance, or from correlation and volatilities.
Open Beta Calculator →Billable Hours Calculator
Billable utilisation, weekly and annual revenue, and your effective rate per hour worked.
Open Billable Hours Calculator →Bond Convexity Calculator
Bond convexity with price, Macaulay and modified duration from coupon, yield and maturity.
Open Bond Convexity Calculator →Bond Duration Calculator
Macaulay and modified duration — how much a bond's price moves when yields move.
Open Bond Duration Calculator →Bond Price Calculator
Bond price from coupon, yield, maturity and frequency — premium or discount versus par.
Open Bond Price Calculator →Bond Yield Calculator
Yield to maturity by solving the bond pricing equation, plus current yield.
Open Bond Yield Calculator →Business Loan Calculator
Business loan payment, total interest and total cost — with fees and extra payments.
Open Business Loan Calculator →Capital Gains Tax Calculator
Capital gains tax from proceeds, basis, expenses and loss offsets — your jurisdiction's rate.
Open Capital Gains Tax Calculator →CAPM Calculator
CAPM expected return from the risk-free rate, beta and expected market return.
Open CAPM Calculator →Car Affordability Calculator
The car price your income supports at a payment cap — loan, down payment and trade-in.
Open Car Affordability Calculator →Cash-on-Cash Return Calculator
Cash-on-cash return on a rental property: annual cash flow divided by the cash you actually invested.
Open Cash-on-Cash Return Calculator →Child Cost Calculator
Estimate what raising a child costs to age 18, by monthly category, with inflation.
Open Child Cost Calculator →Child Tax Credit Calculator
US federal Child Tax Credit estimate, with phase-out by filing status and the refundable portion.
Open Child Tax Credit Calculator →Cleaning Cost Calculator
Estimate house cleaning cost from size, rooms, cleaning type and frequency.
Open Cleaning Cost Calculator →Combined Loan-to-Value Calculator
Combined loan-to-value: all mortgage debt against home value, for second loans and refinancing.
Open Combined Loan-to-Value Calculator →Commission Calculator
Split a sales commission between agent and brokerage, for property, sales and affiliate deals.
Open Commission Calculator →Company Earnings Calculator
Company earnings: gross profit, EBITDA, EBIT and net income with margins.
Open Company Earnings Calculator →Company Valuation Calculator
Estimate enterprise and equity value from EBITDA and revenue multiples.
Open Company Valuation Calculator →Contribution Margin Calculator
Contribution margin, margin ratio and break-even volume for a product or service.
Open Contribution Margin Calculator →Cost of Capital Calculator
Weighted average cost of capital (WACC): the blended cost of equity and after-tax debt.
Open Cost of Capital Calculator →Cost of Equity Calculator
Cost of equity via CAPM: risk-free rate plus beta times the equity risk premium.
Open Cost of Equity Calculator →Cost of Goods Sold Calculator
Cost of goods sold from inventory movement, with gross profit and margin.
Open Cost of Goods Sold Calculator →Creator Ad Revenue Calculator
Estimate creator ad revenue from views and RPM. Estimate only - RPM varies wildly.
Open Creator Ad Revenue Calculator →Credit Spread Calculator
Credit spread: the extra yield a risky bond pays over a risk-free bond of the same maturity.
Open Credit Spread Calculator →Credit Utilization Calculator
Credit utilization across cards: balances divided by limits, overall and per card.
Open Credit Utilization Calculator →Currency Forward Calculator
Currency forward rate from covered interest parity. No-arbitrage rate, not a prediction.
Open Currency Forward Calculator →Debt Payoff Calculator
How long a fixed monthly payment takes to clear a debt, and how much interest it costs.
Open Debt Payoff Calculator →Debt Service Coverage Ratio Calculator
Debt service coverage ratio: operating income divided by total debt service.
Open Debt Service Coverage Ratio Calculator →Depreciation Calculator
Depreciation by straight-line and double declining balance methods, with a year-by-year schedule.
Open Depreciation Calculator →Dividend Discount Model Calculator
Dividend Discount Model (Gordon growth model): value a dividend-paying share from its future dividends.
Open Dividend Discount Model Calculator →Dividend Payout Ratio Calculator
Dividend payout ratio: dividends as a share of earnings, with the retention ratio.
Open Dividend Payout Ratio Calculator →Dividend Yield Calculator
Dividend yield: annual dividend per share divided by share price.
Open Dividend Yield Calculator →Down Payment Calculator
Down payment, loan amount and total cash needed for a home purchase.
Open Down Payment Calculator →DuPont Analysis Calculator
DuPont analysis: break return on equity into margin, turnover and leverage.
Open DuPont Analysis Calculator →Earned Value Management Calculator
Earned value management: cost and schedule performance, forecast final cost.
Open Earned Value Management Calculator →Economic Order Quantity Calculator
Find the order size that minimises total inventory cost — EOQ, orders per year, ordering and holding costs, and total annual cost.
Open Economic Order Quantity Calculator →Effective Corporate Tax Rate Calculator
Work out a company's true tax burden: effective tax rate from pre-tax income and total tax, with a statutory-vs-effective comparison.
Open Effective Corporate Tax Rate Calculator →Efficiency Ratios Calculator
Measure how hard assets work: inventory, receivables and payables turnover, days sales outstanding, days inventory and the cash conversion cycle.
Open Efficiency Ratios Calculator →Electricity Cost Calculator
What does an appliance really cost to run? Enter watts, hours and your tariff to get daily, monthly and annual electricity costs.
Open Electricity Cost Calculator →ELSS Calculator
India: estimate ELSS mutual fund returns for SIP or lump sum, Section 80C tax saved, and the 3-year lock-in that applies to every instalment.
Open ELSS Calculator →Emergency Fund Calculator
How big should your safety net be? Turn monthly essential expenses into a target fund, see how many months you already cover, and plan the gap.
Open Emergency Fund Calculator →EMI Calculator
Loan EMI, total interest and total payment for any loan — with a year-by-year amortisation summary and the effect of extra payments.
Open EMI Calculator →EPF Calculator
India: estimate your Employees' Provident Fund balance — employee and employer contributions, EPS split, and interest at the current declared rate.
Open EPF Calculator →EPS Growth Calculator
Earnings per share growth: CAGR between two periods, year-on-year growth, and projected EPS at a chosen growth rate.
Open EPS Growth Calculator →Fibonacci Retracement Calculator
Plot Fibonacci retracement levels from a swing high and low — 23.6%, 38.2%, 50%, 61.8% and 78.6% — for uptrends and downtrends.
Open Fibonacci Retracement Calculator →FICA Tax Calculator
US federal: estimate Social Security and Medicare (FICA) tax for employees and the self-employed, with the Social Security wage base cap.
Open FICA Tax Calculator →FIRE Calculator
Financial Independence, Retire Early: your FIRE number from annual spending and withdrawal rate, years to reach it, and withdrawal-rate sensitivity.
Open FIRE Calculator →Fixed Deposit Calculator
India-style fixed deposit maturity: principal, interest rate, tenure and compounding frequency — quarterly by default — with interest earned.
Open Fixed Deposit Calculator →Free Cash Flow Calculator
Free cash flow two ways: operating cash flow minus capital expenditure, or from EBIT with tax, depreciation and working capital.
Open Free Cash Flow Calculator →Fuel Cost Calculator
Trip and annual fuel costs: distance, consumption in mpg or L/100 km, and fuel price — plus cost per mile/km and per passenger.
Open Fuel Cost Calculator →Full-Time Equivalent Calculator
Convert any mix of part-time and full-time hours into FTEs — for staffing, budgeting and headcount reporting.
Open Full-Time Equivalent Calculator →Futures Contract Calculator
Futures P&L, margin return and breakeven: entry, exit, contract multiplier, number of contracts and fees — for any futures market.
Open Futures Contract Calculator →Gas vs Electric Dryer Calculator
Gas dryer or electric dryer — which costs less to run? Compare annual energy costs, purchase-price payback and lifetime cost.
Open Gas vs Electric Dryer Calculator →Graham Number Calculator
Benjamin Graham's intrinsic-value estimate: the Graham Number from EPS and book value per share, with margin of safety against the current price.
Open Graham Number Calculator →Gratuity Calculator
India: gratuity under the Payment of Gratuity Act — last drawn salary, years of service, 5-year eligibility and the statutory formula.
Open Gratuity Calculator →Gross Rent Multiplier Calculator
Gross Rent Multiplier (GRM): property price divided by annual gross rent — a quick screening ratio for rental property, with payback intuition.
Open Gross Rent Multiplier Calculator →Gross to Net Pay Calculator
Gross pay to take-home pay: apply your own tax, retirement and other deduction rates — generic, for any country — by pay period.
Open Gross to Net Pay Calculator →GST Calculator
India: GST on any amount — exclusive or inclusive, CGST + SGST for intra-state supply or IGST for inter-state, at any editable rate.
Open GST Calculator →Hedge Ratio Calculator
Find the minimum-variance hedge ratio and how many futures contracts hedge your exposure.
Open Hedge Ratio Calculator →Hot Tub Cost Calculator
Work out what a hot tub really costs: purchase, installation and monthly running costs over its lifetime.
Open Hot Tub Cost Calculator →House Offer Calculator
Price a sensible offer on a house: discount, repairs, closing costs and the monthly mortgage it implies.
Open House Offer Calculator →HR Metrics Calculator
Measure attrition, retention and the cost of turnover from headcount and leaver numbers.
Open HR Metrics Calculator →HRA Exemption Calculator
India: work out how much of your House Rent Allowance is exempt from tax under Section 10(13A).
Open HRA Exemption Calculator →Interest Rate Parity Calculator
Compute the no-arbitrage forward exchange rate implied by two countries’ interest rates.
Open Interest Rate Parity Calculator →Internal Rate of Return Calculator
Find the IRR of a cash-flow series, plus NPV at your discount rate and the year-by-year picture.
Open Internal Rate of Return Calculator →Intrinsic Value Calculator
Estimate a stock’s intrinsic value with a 5-year DCF plus terminal value, and cross-check with the Gordon growth model.
Open Intrinsic Value Calculator →Inventory Valuation Calculator
Compare FIFO, LIFO and weighted-average inventory valuation and cost of goods sold from two cost layers.
Open Inventory Valuation Calculator →Investment Performance Ratios Calculator
Compute Sharpe, Sortino and Treynor ratios from a series of periodic returns.
Open Investment Performance Ratios Calculator →Lease Calculator
Estimate monthly lease payments from capitalised cost, residual value and money factor.
Open Lease Calculator →LED Savings Calculator
See how much switching to LED bulbs saves in energy, money and bulb replacements.
Open LED Savings Calculator →Lemonade Stand Profit Calculator
Price cups, count costs and find the profit — and break-even point — of a lemonade stand.
Open Lemonade Stand Profit Calculator →Leverage Ratios Calculator
Measure financial leverage: debt-to-equity, debt ratio, equity multiplier and debt-to-EBITDA.
Open Leverage Ratios Calculator →Liquid Net Worth Calculator
Separate what you can actually spend from total net worth: liquid assets minus liquid liabilities.
Open Liquid Net Worth Calculator →Liquidity Ratios Calculator
Test short-term financial health: current, quick and cash ratios plus working capital.
Open Liquidity Ratios Calculator →Loan Balance Calculator
Find your remaining loan balance after a given number of payments, and the interest already paid.
Open Loan Balance Calculator →Loan-to-Value Calculator
Compute loan-to-value from home value and down payment or loan amount, and see if PMI is likely.
Open Loan-to-Value Calculator →Lumpsum Investment Calculator
Project the future value of a one-time investment at a chosen return, with inflation-adjusted value too.
Open Lumpsum Investment Calculator →Market Capitalization Calculator
Compute a company’s market capitalisation from share price and shares outstanding, including free-float cap.
Open Market Capitalization Calculator →Markup Calculator
Convert between cost, markup, selling price and margin — both directions.
Open Markup Calculator →Maximum Drawdown Calculator
Find the worst peak-to-trough fall in a portfolio or price series — the maximum drawdown.
Open Maximum Drawdown Calculator →Meeting Cost Calculator
Put a price on meetings: attendees, pay rates, duration and frequency — per meeting and per year.
Open Meeting Cost Calculator →Millionaire Calculator
Work out how long it takes to reach $1,000,000 — or what any savings plan is worth in a given time.
Open Millionaire Calculator →Money Counter Calculator
Count cash fast: enter how many of each bill and coin you have and get the total.
Open Money Counter Calculator →Money Weight Calculator
Work out how much a sum of cash weighs, in notes and coins.
Open Money Weight Calculator →Mortgage Points Calculator
Compare buying mortgage points against keeping a higher rate — cost, saving and breakeven.
Open Mortgage Points Calculator →Mortgage Prepayment Penalty Calculator
Estimate a mortgage prepayment penalty by percentage, months of interest, or both.
Open Mortgage Prepayment Penalty Calculator →Moving Average Calculator
Compute SMA and EMA from any price series, with a crossover signal.
Open Moving Average Calculator →National Insurance Calculator (UK)
UK National Insurance on your salary — employee (and employer) contributions at current thresholds.
Open National Insurance Calculator (UK) →Net Effective Rent Calculator
Turn headline rent, free months and concessions into the true monthly cost.
Open Net Effective Rent Calculator →Net Operating Income Calculator
NOI for a rental property: income minus operating expenses, before debt service.
Open Net Operating Income Calculator →Net Worth Calculator
Add up everything you own, subtract everything you owe — your net worth.
Open Net Worth Calculator →NPS Calculator (India)
India’s National Pension System: project your retirement corpus and monthly pension.
Open NPS Calculator (India) →Occupancy Rate Calculator
Occupancy rate for rentals, hotels or any unit-based business.
Open Occupancy Rate Calculator →Options Pricing Calculator (Black-Scholes)
Black-Scholes call and put prices plus the Greeks — delta, gamma, theta, vega, rho.
Open Options Pricing Calculator (Black-Scholes) →Options Spread Calculator
Payoff, breakeven, max profit and max loss for a two-leg options spread.
Open Options Spread Calculator →Overtime Pay Calculator
Regular pay, overtime at time-and-a-half (or your multiplier) and double time.
Open Overtime Pay Calculator →Parking Ratio Calculator
Parking spaces per 1,000 sq ft — and per unit — for any building.
Open Parking Ratio Calculator →Payback Period Calculator
How long until an investment pays for itself — simple and discounted payback.
Open Payback Period Calculator →Payday Loan Calculator
The true cost of a payday loan: fee, total due and effective APR — with an honest warning.
Open Payday Loan Calculator →Period Products Cost Calculator
What periods really cost: pads, tampons, cups and discs over a year and a lifetime.
Open Period Products Cost Calculator →Perpetuity Calculator
Present value of a payment that never ends — flat or growing.
Open Perpetuity Calculator →Pivot Point Calculator
Pivot, support and resistance levels — Standard, Fibonacci, Camarilla and Woodie.
Open Pivot Point Calculator →Post Office Monthly Income Scheme Calculator (India)
India Post Office MIS: monthly income on your deposit at the current rate.
Open Post Office Monthly Income Scheme Calculator (India) →PPF Calculator (India)
India’s Public Provident Fund: maturity value on yearly deposits at the current rate.
Open PPF Calculator (India) →Precious Metal Melt Value Calculator
What your gold, silver, platinum or palladium is worth as pure metal.
Open Precious Metal Melt Value Calculator →Private Mortgage Insurance Calculator (US)
US PMI: monthly cost, LTV, and how much principal you must pay to drop it.
Open Private Mortgage Insurance Calculator (US) →Prorated Amount Calculator
Prorate any amount — salary, rent, subscription — for a partial period.
Open Prorated Amount Calculator →Rate of Return Calculator
Total return and CAGR for any investment — simple, honest, annualised.
Open Rate of Return Calculator →Real Estate Commission Calculator
Work out the total real estate commission on a sale, how it splits between listing and buyer agents, and what each agent keeps after the brokerage cut.
Open Real Estate Commission Calculator →Rental Property Calculator
Analyse a rental property: gross yield, vacancy-adjusted income, net operating income, cap rate, monthly cash flow and cash-on-cash return.
Open Rental Property Calculator →Retained Earnings Calculator
Roll retained earnings forward: beginning balance plus net income minus dividends equals ending retained earnings, with payout ratio.
Open Retained Earnings Calculator →Return Ratios Calculator
Compute return on equity (ROE), return on assets (ROA), net profit margin and equity multiplier from one set of company figures.
Open Return Ratios Calculator →RSI Calculator
Compute the Relative Strength Index (RSI) with Wilder smoothing from a price series, with overbought, oversold and neutral bands.
Open RSI Calculator →Sales Calculator
Work out sales revenue: units sold, unit price, discount and tax, with gross, discounted and final totals and average revenue per unit.
Open Sales Calculator →Shower Cost Calculator
Work out what each shower costs in water and water heating, plus weekly and annual totals, from duration, flow rate and your tariffs.
Open Shower Cost Calculator →SIP Calculator
Project a Systematic Investment Plan: monthly investment, expected return and step-up, with maturity value, amount invested, gains, and a lump-sum and inflation-adjusted comparison.
Open SIP Calculator →Stamp Duty Land Tax Calculator
UK Stamp Duty Land Tax on a residential purchase, using the current UK bands as editable inputs, with first-time buyer relief and the additional-property surcharge.
Open Stamp Duty Land Tax Calculator →Stock Valuation Ratios Calculator
Value a share with price-to-earnings (P/E), price-to-book (P/B), dividend yield and PEG, from price, earnings, book value, dividend and growth.
Open Stock Valuation Ratios Calculator →Streaming Royalties Calculator
Estimate streaming royalties from stream counts and per-stream rates, by platform preset or a custom rate, with the artist share after a label or distributor cut.
Open Streaming Royalties Calculator →Subscription Cost Calculator
Add up what subscriptions really cost each month and year, and how much is wasted on services you barely use.
Open Subscription Cost Calculator →Sukanya Samriddhi Yojana Calculator
India: project a Sukanya Samriddhi Yojana (SSY) account — yearly deposit, current interest rate as an editable input, maturity value, total deposited and interest earned.
Open Sukanya Samriddhi Yojana Calculator →Sustainable Growth Rate Calculator
Compute the sustainable growth rate (SGR): how fast a company can grow sales using only retained earnings, from ROE and dividend payout.
Open Sustainable Growth Rate Calculator →Tax Bracket Calculator
Work out tax under progressive brackets with fully editable thresholds and rates — no single country hard-coded — plus marginal and effective rates.
Open Tax Bracket Calculator →Taxable Equivalent Yield Calculator
Compare tax-free and taxable bonds fairly: taxable equivalent yield, and the tax-free yield a taxable bond would need to match.
Open Taxable Equivalent Yield Calculator →TDS on Interest Calculator
India: estimate TDS deducted on interest income — threshold, TDS rate and net interest received, with the rate and threshold as editable inputs.
Open TDS on Interest Calculator →Tesla Charging Cost Calculator
Work out what charging a Tesla costs: monthly and annual charging cost, cost per mile, and a petrol-car comparison, by model efficiency and electricity price.
Open Tesla Charging Cost Calculator →Time Value of Money Calculator
Solve any one time-value-of-money variable — present value, future value, payment, number of periods or rate — for an ordinary annuity or lump sum.
Open Time Value of Money Calculator →UK Coin Weight Calculator
UK: weigh a pile of coins — enter how many of each denomination you have and get total value, total weight in grams and kilograms, and coin count.
Open UK Coin Weight Calculator →VA Loan Calculator
US: estimate a VA home loan — monthly payment with the VA funding fee financed into the loan, or waived for exempt veterans.
Open VA Loan Calculator →Working Capital Calculator
Work out working capital, the current ratio and the quick ratio from current assets, current liabilities and inventory.
Open Working Capital Calculator →4Ts Score Calculator
Score heparin-induced thrombocytopenia (HIT) risk with the published 4Ts system — thrombocytopenia, timing, thrombosis and other causes — with an interpretation band.
Open 4Ts Score Calculator →5/3/1 Lifting Calculator
Jim Wendler 5/3/1 training weights: enter a one-rep max and get all four weeks — 5s, 3s, 5/3/1 and deload — from a 90% training max.
Open 5/3/1 Lifting Calculator →6-Minute Walk Test Calculator
Predict 6-minute walk distance from the published Enright reference equations, compare your actual distance, and see the percentage of predicted with interpretation bands.
Open 6-Minute Walk Test Calculator →A Body Shape Index (ABSI) Calculator
Compute your A Body Shape Index from waist, height and weight, with BMI and an interpretation of where your ABSI sits.
Open A Body Shape Index (ABSI) Calculator →Absolute Eosinophil Count Calculator
Convert a white cell count and eosinophil percentage into an absolute eosinophil count, with standard interpretation bands.
Open Absolute Eosinophil Count Calculator →Absolute Lymphocyte Count Calculator
Convert a white cell count and lymphocyte percentage into an absolute lymphocyte count, with standard adult bands.
Open Absolute Lymphocyte Count Calculator →Absolute Neutrophil Count (ANC) Calculator
Compute the absolute neutrophil count from WBC, segmented neutrophils and bands, with standard neutropenia bands.
Open Absolute Neutrophil Count (ANC) Calculator →Acetaminophen Dosage Calculator
Work out standard adult and weight-based paediatric acetaminophen (paracetamol) doses from published dosing ranges.
Open Acetaminophen Dosage Calculator →Acetaminophen Overdose Calculator
Plot a serum acetaminophen level on the revised Rumack–Matthew nomogram treatment line — with urgent safety guidance.
Open Acetaminophen Overdose Calculator →Acid-Base (ABG) Calculator
Interpret an arterial blood gas: calculated pH, anion gap, Winter’s formula compensation check, and primary disorder.
Open Acid-Base (ABG) Calculator →Adderall Dosage Calculator
Check published Adderall / Adderall XR starting doses and daily maximums by age, form and indication — with a dose-limit check.
Open Adderall Dosage Calculator →Adjusted Age Calculator (Premature Babies)
Convert a premature baby’s chronological age into adjusted (corrected) age from gestational age at birth.
Open Adjusted Age Calculator (Premature Babies) →Adjusted Body Weight Calculator
Compute ideal body weight (Devine) and adjusted body weight for drug dosing in patients above ideal weight.
Open Adjusted Body Weight Calculator →Adrenal Washout Calculator
Compute absolute and relative adrenal washout from CT attenuation values and check them against adenoma thresholds.
Open Adrenal Washout Calculator →Age-Adjusted D-Dimer Calculator
Find the age-adjusted D-dimer cut-off for patients over 50 and compare a result against it, with the standard 500 cut-off under 50.
Open Age-Adjusted D-Dimer Calculator →Albumin-Globulin Ratio Calculator
Compute the albumin/globulin ratio from albumin and total protein, with the usual reference band.
Open Albumin-Globulin Ratio Calculator →Alcohol Units Calculator
Convert a drink’s volume and strength into UK alcohol units, US standard drinks and grams of pure alcohol.
Open Alcohol Units Calculator →Aldrete Score Calculator
Score post-anaesthesia recovery with the modified Aldrete score across activity, respiration, circulation, consciousness and oxygen saturation.
Open Aldrete Score Calculator →Aleve (Naproxen) Dosage Calculator
Check the over-the-counter naproxen (Aleve) regimen and how much of the daily maximum remains after tablets already taken.
Open Aleve (Naproxen) Dosage Calculator →Alvarado Score Calculator
Score suspected appendicitis with the Alvarado (MANTRELS) score and see the standard probability bands.
Open Alvarado Score Calculator →Alveolar-Arterial Gradient Calculator
Compute the alveolar–arterial oxygen gradient from FiO2, PaCO2 and PaO2, with an age-based expected value.
Open Alveolar-Arterial Gradient Calculator →Alzheimer’s Life Expectancy Calculator
Look up published median survival after a mild-to-moderate Alzheimer’s diagnosis by sex, age group and comorbidity count — a population statistic, not a personal prognosis.
Open Alzheimer’s Life Expectancy Calculator →Amoxicillin Pediatric Dosage Calculator
Compute published paediatric amoxicillin daily and per-dose ranges from a child’s weight, for standard and high-dose regimens.
Open Amoxicillin Pediatric Dosage Calculator →Anaerobic Threshold Calculator
Estimate your anaerobic (lactate) threshold heart-rate zone from age, resting heart rate and training level — an estimate, not a lab test.
Open Anaerobic Threshold Calculator →Anion Gap Calculator
Compute the serum anion gap, with albumin correction, and see whether it falls in the normal range.
Open Anion Gap Calculator →Ankle-Brachial Index Calculator
Compute left and right ankle-brachial indices from arm and ankle pressures, with published peripheral artery disease bands.
Open Ankle-Brachial Index Calculator →APACHE II Score Calculator
Calculate the APACHE II severity score from admission physiology, age and chronic health — with an approximate mortality band for context.
Open APACHE II Score Calculator →Ape Index Calculator
Work out your ape index — wingspan divided by height — and see how your reach compares with the typical 1.0 ratio for climbers and athletes.
Open Ape Index Calculator →Apgar Score Calculator
Score the five Apgar signs at 1 and 5 minutes — appearance, pulse, grimace, activity and respiration — each 0 to 2, for a total out of 10.
Open Apgar Score Calculator →Apnea-Hypopnea Index (AHI) Calculator
Turn a sleep study into an AHI: total apneas plus hypopneas divided by hours of sleep, with the standard mild, moderate and severe bands.
Open Apnea-Hypopnea Index (AHI) Calculator →APRI Score Calculator
Calculate the APRI liver fibrosis score from AST and platelet count — a simple, published blood-test ratio used alongside clinical assessment.
Open APRI Score Calculator →Archery Draw Length Calculator
Estimate your archery draw length from wingspan — the standard wingspan divided by 2.5 rule — plus a suggested arrow length.
Open Archery Draw Length Calculator →AST-ALT Ratio Calculator
Calculate the AST/ALT (De Ritis) ratio from liver blood tests and see the classic interpretation bands — with the caveats that matter.
Open AST-ALT Ratio Calculator →AUDIT Alcohol Screening Calculator
Score the WHO AUDIT questionnaire — 10 questions, 0 to 40 — with the standard low-risk, hazardous, harmful and possible-dependence bands.
Open AUDIT Alcohol Screening Calculator →Average Triathlon Finish Time Calculator
Build your predicted triathlon finish time from your swim, bike and run paces plus transitions — and compare it with typical mid-pack finish times.
Open Average Triathlon Finish Time Calculator →Baby Eye Color Predictor
Estimate a baby’s likely eye colour from the parents’ eye colours and whether each parent has a blue-eyed parent — as probabilities, never a certainty.
Open Baby Eye Color Predictor →Baby Formula Calculator
Work out how much formula your baby needs per day and per feed from weight and feeds per day — using the standard weight-based guide.
Open Baby Formula Calculator →Baby Milk Intake Calculator
Estimate how much milk your baby needs per day and per feed from weight and age — for breast milk, formula, or mixed feeding.
Open Baby Milk Intake Calculator →Barthel Index Calculator
Score the 10-item Barthel Index of daily living activities — feeding, bathing, dressing, mobility and more — for a total out of 100.
Open Barthel Index Calculator →BASDAI Score Calculator
Score the Bath Ankylosing Spondylitis Disease Activity Index — six 0-to-10 questions on fatigue, pain, stiffness and more.
Open BASDAI Score Calculator →Beighton Score Calculator
Score the 9-point Beighton scale for joint hypermobility — little fingers, thumbs, elbows, knees and trunk flexion, left and right.
Open Beighton Score Calculator →Benadryl Dosage Calculator
Check the published diphenhydramine (Benadryl) dose range by age and weight — single-dose and daily-maximum guidance, with the under-2 warning.
Open Benadryl Dosage Calculator →Bench Press Calculator
Estimate your bench press one-rep max from a submaximal set — Epley, Brzycki and Lander formulas — plus training loads at 60–90% of 1RM.
Open Bench Press Calculator →Benzodiazepine Conversion Calculator
Convert between benzodiazepines using published diazepam-equivalent doses (Ashton) — with the clear warning that equivalents are approximate.
Open Benzodiazepine Conversion Calculator →Berg Balance Scale Calculator
Score the 14-item Berg Balance Scale — sitting, standing, reaching, turning and stepping — each 0 to 4, for a total out of 56.
Open Berg Balance Scale Calculator →Bicarbonate Deficit Calculator
Estimate the bicarbonate deficit in metabolic acidosis from serum bicarbonate, body weight and target — plus the equivalent volume of 8.4% solution.
Open Bicarbonate Deficit Calculator →Bike Cadence Calculator
Convert between cycling cadence and speed from chainring, cog and wheel size — or work out the gear ratio and distance per pedal revolution.
Open Bike Cadence Calculator →Birth Control Cost Calculator
Compare the true cost of birth control over time — upfront plus monthly costs, insurance cover, and cost per year for your chosen method.
Open Birth Control Cost Calculator →Bishop Score Calculator
Score the five Bishop components for induction readiness — dilation, effacement, station, consistency and position — for a total out of 13.
Open Bishop Score Calculator →Bladder Volume Calculator
Estimate bladder volume from ultrasound length, width and height, with post-void residual interpretation.
Open Bladder Volume Calculator →Blood Donation Eligibility Calculator
Check general blood donation eligibility by age, weight, donation interval and haemoglobin, with the wait until the next donation.
Open Blood Donation Eligibility Calculator →Blood Loss Calculator
Estimate blood volume, allowable blood loss from haemoglobin change, and the percentage lost with its shock class.
Open Blood Loss Calculator →Blood pH Calculator
Calculate blood pH from bicarbonate and carbon dioxide with the Henderson-Hasselbalch equation, plus acid-base interpretation and optional anion gap.
Open Blood pH Calculator →Blood Pressure Calculator
Classify blood pressure, and calculate mean arterial pressure and pulse pressure, from systolic and diastolic readings.
Open Blood Pressure Calculator →Blood Sugar Calculator
Convert blood glucose between mg/dL and mmol/L, classify fasting, random and post-meal readings, and estimate average glucose from HbA1c.
Open Blood Sugar Calculator →Blood Volume Calculator
Estimate total blood volume with the Nadler formula, alongside the simple weight-based estimate, from sex, height and weight.
Open Blood Volume Calculator →BODE Index Calculator
Score COPD severity with the published BODE index from BMI, lung function, breathlessness and walk distance, with its prognostic quartile.
Open BODE Index Calculator →Body Adiposity Index (BAI) Calculator
Estimate body fat percentage with the Body Adiposity Index from hip circumference and height, without needing weight.
Open Body Adiposity Index (BAI) Calculator →Body Frame Size Calculator
Determine small, medium or large body frame from height and wrist circumference, which refines healthy weight ranges.
Open Body Frame Size Calculator →Body Roundness Index (BRI) Calculator
Calculate the Body Roundness Index from waist and height, a shape-based complement to BMI that reflects central fat.
Open Body Roundness Index (BRI) Calculator →Body Surface Area (BSA) Calculator
Calculate body surface area with the Mosteller, Du Bois and Haycock formulas from height and weight.
Open Body Surface Area (BSA) Calculator →Body Water Percentage Calculator
Estimate total body water and body water percentage with the Watson formula from age, sex, height and weight.
Open Body Water Percentage Calculator →Braden Scale Calculator
Score pressure injury risk with the published Braden Scale across sensory perception, moisture, activity, mobility, nutrition and friction.
Open Braden Scale Calculator →Breast Cancer Recurrence Risk Calculator
Estimate breast cancer prognostic group with the published Nottingham Prognostic Index from tumour size, grade and nodal involvement.
Open Breast Cancer Recurrence Risk Calculator →Breast Pump Flange Size Calculator
Find the right breast pump flange size from nipple diameter, using the standard 2-4 mm clearance guide and common flange sizes.
Open Breast Pump Flange Size Calculator →Breastfeeding Calorie Calculator
Estimate daily calorie needs while breastfeeding from basal metabolic rate, activity level and lactation stage.
Open Breastfeeding Calorie Calculator →Brief Interview for Mental Status (BIMS) Calculator
Score the Brief Interview for Mental Status from word repetition, temporal orientation and recall, with its published bands.
Open Brief Interview for Mental Status (BIMS) Calculator →Bruce Protocol METs Calculator
Estimate VO2 max and METs from Bruce treadmill test time with the published Pollock equations, plus an age-predicted maximum heart rate.
Open Bruce Protocol METs Calculator →Caffeine Intake Calculator
Add up daily caffeine from coffee, tea, cola and energy drinks, and compare it with the 400 mg adult guideline or the 200 mg pregnancy guideline.
Open Caffeine Intake Calculator →CAGE Questionnaire Calculator
Score the four-question CAGE alcohol screen, where two or more yes answers indicate a positive screen needing fuller assessment.
Open CAGE Questionnaire Calculator →Carboplatin Dose Calculator
Calculate carboplatin dose with the Calvert formula from target AUC and kidney function, with capped GFR and creatinine-clearance method choice.
Open Carboplatin Dose Calculator →Cardiac Output Calculator
Calculate cardiac output from heart rate and stroke volume, with ejection fraction and cardiac index when end-diastolic volume and body size are given.
Open Cardiac Output Calculator →Cefdinir Dosage Calculator
Calculate labelled cefdinir dosing for adults and children from age group, weight, indication and kidney function, with caps and renal reductions.
Open Cefdinir Dosage Calculator →Centor Score Calculator
Estimate strep throat likelihood with the classic Centor criteria — fever, exudate, tender nodes and no cough — in seconds.
Open Centor Score Calculator →Cerebral Perfusion Pressure Calculator
Calculate cerebral perfusion pressure from blood pressure and intracranial pressure, with the usual 60-70 mmHg target range.
Open Cerebral Perfusion Pressure Calculator →CHA2DS2-VASc Score Calculator
Score stroke risk in atrial fibrillation with the published CHA2DS2-VASc table, including annual risk estimates.
Open CHA2DS2-VASc Score Calculator →Charlson Comorbidity Index Calculator
Combine age and 17 comorbidity groups into the Charlson index, with an estimated 10-year survival figure.
Open Charlson Comorbidity Index Calculator →Child BMI Percentile Calculator
Work out a child’s BMI percentile for ages 2-20, with CDC-style weight categories explained in plain language.
Open Child BMI Percentile Calculator →Child Growth Percentile Calculator
Estimate height and weight percentiles for children up to 18, with plain-language guidance on what a percentile does and does not mean.
Open Child Growth Percentile Calculator →Child-Pugh Score Calculator
Score liver cirrhosis severity with the published Child-Pugh table, including class and survival estimates.
Open Child-Pugh Score Calculator →Cholesterol Ratio Calculator
Turn total, HDL and LDL cholesterol into total/HDL and LDL/HDL ratios plus non-HDL cholesterol, in mg/dL or mmol/L.
Open Cholesterol Ratio Calculator →Circadian Rhythm Calculator
Plan bedtime, wake time, light, exercise and caffeine cut-off around your natural circadian rhythm.
Open Circadian Rhythm Calculator →CIWA-Ar Alcohol Withdrawal Calculator
Score alcohol withdrawal severity with the 10-item CIWA-Ar scale, from minimal to severe.
Open CIWA-Ar Alcohol Withdrawal Calculator →Conception Date Calculator
Estimate a conception date from the last menstrual period or a due date, with the fertile window around ovulation.
Open Conception Date Calculator →Corrected Calcium Calculator
Adjust total calcium for albumin with the Payne formula, in mg/dL or mmol/L, with albumin in g/dL or g/L.
Open Corrected Calcium Calculator →Corrected Magnesium Calculator
Adjust total magnesium for albumin with the Kroll and Elin formula, in mg/dL or mmol/L.
Open Corrected Magnesium Calculator →Creatinine Clearance Calculator
Estimate kidney function with Cockcroft-Gault creatinine clearance and the 2021 CKD-EPI eGFR, with unit handling.
Open Creatinine Clearance Calculator →Crohn’s Disease Activity Index Calculator
Score Crohn’s disease activity with the classic Best CDAI weights, from remission to severe disease.
Open Crohn’s Disease Activity Index Calculator →Crown-Rump Length Calculator
Convert crown-rump length to gestational age, or gestational age to expected CRL, with an estimated due date.
Open Crown-Rump Length Calculator →CURB-65 Score Calculator
Score community-acquired pneumonia severity with CURB-65, including 30-day mortality estimates and care setting.
Open CURB-65 Score Calculator →Cycling Breakaway Calculator
Work out whether a breakaway survives: catch time, catch distance and time to the finish at constant speeds.
Open Cycling Breakaway Calculator →Cycling Life Gain Calculator
Estimate the life-time gained from regular cycling, using the Utrecht finding that each hour ridden returns about an hour of life.
Open Cycling Life Gain Calculator →Cycling Power Calculator
Estimate cycling power from speed, weight, gradient and wind using standard cycling physics, plus watts per kilo.
Open Cycling Power Calculator →Cycling Training Zones Calculator
Turn functional threshold power (FTP) into Coggan-style power training zones, with watts per kilo.
Open Cycling Training Zones Calculator →Daily Sugar Intake Calculator
Compare your added sugar intake with WHO and American Heart Association limits, in grams and teaspoons.
Open Daily Sugar Intake Calculator →DAPT Score Calculator
Score the benefit of prolonging dual antiplatelet therapy after coronary stenting, using the published DAPT score.
Open DAPT Score Calculator →Dead Space Calculator
Calculate physiological dead space with the Bohr equation, plus dead-space volume and alveolar ventilation.
Open Dead Space Calculator →Denver HIV Risk Score Calculator
Estimate the likelihood of undiagnosed HIV infection with the published Denver HIV Risk Score, with a testing threshold at 30.
Open Denver HIV Risk Score Calculator →Diabetes Risk Calculator
Estimate 10-year type 2 diabetes risk with the published FINDRISC questionnaire, including age, BMI, waist, activity and family history.
Open Diabetes Risk Calculator →Diabetic Ketoacidosis Calculator
Check DKA severity from pH and bicarbonate and estimate corrected sodium, effective osmolality and water deficit for education.
Open Diabetic Ketoacidosis Calculator →Diaper Usage Calculator
Estimate how many diapers a baby uses per day, month and year, plus the cost, from age-based averages or your own daily count.
Open Diaper Usage Calculator →DIC Score Calculator
Score overt disseminated intravascular coagulation with the ISTH algorithm from platelets, D-dimer, prothrombin time and fibrinogen.
Open DIC Score Calculator →Diet Risk Score Calculator
Score overall dietary pattern from fruit and vegetables, whole grains, sugary drinks, processed meat, fish and cooking habits.
Open Diet Risk Score Calculator →Diffuse Large B-Cell Lymphoma Prognosis Calculator
Estimate the International Prognostic Index (IPI) for diffuse large B-cell lymphoma from age, stage, LDH, performance status and extranodal sites.
Open Diffuse Large B-Cell Lymphoma Prognosis Calculator →Dog Walking Benefits Calculator
Estimate calories burned, steps, distance and weekly activity from your dog walks, including the health activity target.
Open Dog Walking Benefits Calculator →Drug Half-Life Calculator
Work out how much of a single dose remains after a given time, and how long until it falls to a target percentage.
Open Drug Half-Life Calculator →DUDIT Drug Use Screening Calculator
Score the 11-item Drug Use Disorders Identification Test (DUDIT) and see whether the result reaches the published screening cut-offs.
Open DUDIT Drug Use Screening Calculator →Duke Activity Status Index Calculator
Score the 12-item Duke Activity Status Index (DASI) and estimate peak oxygen uptake and functional capacity in METs.
Open Duke Activity Status Index Calculator →Duke Treadmill Score Calculator
Calculate the Duke Treadmill Score from exercise time, ST-segment deviation and angina, with its published risk groups.
Open Duke Treadmill Score Calculator →EASI Score Calculator
Score eczema severity with the Eczema Area and Severity Index (EASI) across the head, trunk, upper and lower limbs.
Open EASI Score Calculator →ECG Heart Rate Calculator
Convert an ECG RR interval or small-square count into heart rate, and correct the QT interval with Bazett’s formula.
Open ECG Heart Rate Calculator →Edinburgh Postnatal Depression Scale (EPDS) Calculator
Score the 10-item Edinburgh Postnatal Depression Scale (EPDS) used to screen for postnatal depression, with its published thresholds.
Open Edinburgh Postnatal Depression Scale (EPDS) Calculator →Effective Regurgitant Orifice Area (EROA) Calculator
Calculate effective regurgitant orifice area and regurgitant volume from the PISA method for mitral regurgitation.
Open Effective Regurgitant Orifice Area (EROA) Calculator →Egg Freezing Calculator
Model how many frozen eggs translate into expected embryos and the chance of at least one live birth, with adjustable assumptions.
Open Egg Freezing Calculator →Endotracheal Tube Size Calculator
Estimate endotracheal tube size and oral insertion depth for children by age, and typical adult sizes by sex.
Open Endotracheal Tube Size Calculator →EORTC Bladder Cancer Prognosis Calculator
Score recurrence and progression risk for non-muscle-invasive bladder cancer with the published EORTC risk tables.
Open EORTC Bladder Cancer Prognosis Calculator →Epworth Sleepiness Scale Calculator
Score daytime sleepiness with the 8-item Epworth Sleepiness Scale and see the published severity bands.
Open Epworth Sleepiness Scale Calculator →Estimated Energy Requirement (EER) Calculator
Estimate daily energy needs for adults with the Institute of Medicine EER equations, adjusted for activity and weight goal.
Open Estimated Energy Requirement (EER) Calculator →EtG Alcohol Test Calculator
Estimate how long ethyl glucuronide (EtG) may remain detectable after drinking, with honest uncertainty ranges — never a pass or fail promise.
Open EtG Alcohol Test Calculator →Exclusive Pumping Calculator
Plan exclusive pumping: daily milk needs, output per session, surplus or shortfall, and how long a freezer stash lasts.
Open Exclusive Pumping Calculator →Fagerstrom Nicotine Dependence Test Calculator
Score nicotine dependence with the 6-item Fagerstrom Test for Nicotine Dependence (FTND) and its published bands.
Open Fagerstrom Nicotine Dependence Test Calculator →Fatigue Severity Scale Calculator
Score fatigue impact with the 9-item Fatigue Severity Scale (FSS), reporting the mean score and total.
Open Fatigue Severity Scale Calculator →Fertility by Age Calculator
See how typical conception chances and miscarriage risk change with age, using published population averages.
Open Fertility by Age Calculator →FEV1/FVC Ratio Calculator
Calculate the FEV1/FVC ratio from spirometry and see whether the pattern suggests airflow obstruction.
Open FEV1/FVC Ratio Calculator →FIB-4 Score Calculator
Calculate the FIB-4 index from age, AST, ALT and platelets to stratify liver fibrosis risk.
Open FIB-4 Score Calculator →Finnegan NAS Score Calculator
Score neonatal abstinence syndrome with the classic 21-item Finnegan scale and its usual treatment thresholds.
Open Finnegan NAS Score Calculator →Fish Oil Dosage Calculator
Work out how many fish oil capsules a day give a published EPA plus DHA target for general health or triglyceride support.
Open Fish Oil Dosage Calculator →Flight Radiation Calculator
Estimate the cosmic radiation dose of a flight from its duration and route latitude, with everyday comparisons.
Open Flight Radiation Calculator →Fractional Excretion of Sodium Calculator
Calculate fractional excretion of sodium (FeNa) to help separate prerenal injury from acute tubular necrosis.
Open Fractional Excretion of Sodium Calculator →Fractional Excretion of Urea Calculator
Calculate fractional excretion of urea (FeUrea), the prerenal marker that stays useful when diuretics distort FeNa.
Open Fractional Excretion of Urea Calculator →Frailty Index Calculator
Build a 20-item deficit-accumulation frailty index and see the robust, pre-frail and frail bands.
Open Frailty Index Calculator →Framingham Risk Score Calculator
Estimate 10-year general cardiovascular risk with the Framingham (D’Agostino 2008) points system.
Open Framingham Risk Score Calculator →Free Testosterone Calculator
Calculate free testosterone from total testosterone, SHBG and albumin with the Vermeulen equation.
Open Free Testosterone Calculator →Free Water Deficit Calculator
Calculate the free water deficit in hypernatraemia from body weight, sex, age group and serum sodium.
Open Free Water Deficit Calculator →Fresh Frozen Plasma Dose Calculator
Work out a fresh frozen plasma dose in millilitres and approximate units from body weight and the usual mL/kg range.
Open Fresh Frozen Plasma Dose Calculator →Fundal Height Calculator
Compare a measured symphysis-fundal height with the expected height for gestational age.
Open Fundal Height Calculator →Gabapentin Dosage Calculator
Check the published gabapentin daily dose range by kidney function, with per-dose splits for divided dosing.
Open Gabapentin Dosage Calculator →GAD-7 Anxiety Calculator
Score the 7-item GAD-7 anxiety questionnaire over the last two weeks and see the standard severity bands.
Open GAD-7 Anxiety Calculator →Gastric Sleeve Weight Loss Calculator
Calculate percent total and percent excess weight loss after gastric sleeve surgery from pre-op and current weight.
Open Gastric Sleeve Weight Loss Calculator →Glasgow Coma Scale Calculator
Score the Glasgow Coma Scale from eye, verbal and motor responses and see the mild, moderate and severe bands.
Open Glasgow Coma Scale Calculator →Glucose Infusion Rate Calculator
Convert between dextrose infusion rate and glucose infusion rate (mg/kg/min) for IV dextrose infusions.
Open Glucose Infusion Rate Calculator →Glycemic Load Calculator
Calculate glycemic load from a food’s glycemic index and carbohydrate content, with an optional second food for a meal total.
Open Glycemic Load Calculator →Gorlin Formula Calculator
Calculate aortic or mitral valve area with the Gorlin formula from cardiac output, mean gradient and ejection or filling time.
Open Gorlin Formula Calculator →Gout Diagnosis Calculator
Apply the 2015 ACR/EULAR gout classification criteria: enter the clinical, laboratory and imaging features and score against the threshold of 8.
Open Gout Diagnosis Calculator →GRACE Score Calculator
Calculate the GRACE in-hospital mortality score for acute coronary syndrome from eight admission variables.
Open GRACE Score Calculator →Gut Microbiome Score Calculator
Estimate a transparent gut-health lifestyle score from diet diversity, fibre, fermented foods and other everyday factors.
Open Gut Microbiome Score Calculator →Hair Growth Calculator
Project how long your hair will grow over time from its current length and an average monthly growth rate.
Open Hair Growth Calculator →Hand Sanitizer Dilution Calculator
Dilute a stronger alcohol stock to a target hand-sanitiser strength with the C1V1 = C2V2 dilution equation.
Open Hand Sanitizer Dilution Calculator →Happiness Score Calculator
Turn six quick self-ratings for mood, satisfaction, relationships, purpose, energy and stress into a transparent well-being score.
Open Happiness Score Calculator →HAS-BLED Score Calculator
Score bleeding risk on anticoagulation with the published HAS-BLED items and their published annual bleeding rates.
Open HAS-BLED Score Calculator →hCG Levels Calculator
Work out hCG doubling time and percentage rise between two blood tests, and compare the rise with the expected early-pregnancy pattern.
Open hCG Levels Calculator →Heart Failure Life Expectancy Calculator
See published population survival ranges by heart-failure severity class — population statistics, never a personal prognosis.
Open Heart Failure Life Expectancy Calculator →Heart Rate Recovery Calculator
Measure heart-rate recovery after exercise — the drop from peak heart rate at one and two minutes — and flag abnormal recovery.
Open Heart Rate Recovery Calculator →Height Estimation for Bedridden Patients Calculator
Estimate standing height for bedridden patients from knee height with the published Chumlea equations.
Open Height Estimation for Bedridden Patients Calculator →Hematocrit-Hemoglobin Calculator
Convert between haemoglobin and haematocrit with the rule of three, and work out MCHC when both values are known.
Open Hematocrit-Hemoglobin Calculator →Hemoglobin A1c Calculator
Convert HbA1c to estimated average glucose (eAG) and back, in mg/dL and mmol/L, with the ADAG equation.
Open Hemoglobin A1c Calculator →Hepatic Steatosis Index Calculator
Score fatty-liver likelihood with the published Hepatic Steatosis Index from ALT, AST, BMI, sex and diabetes status.
Open Hepatic Steatosis Index Calculator →Hiking Time Calculator
Estimate hiking time with Naismith’s rule — distance pace plus an hour per 600 metres of ascent — with breaks added.
Open Hiking Time Calculator →Hormone Ratio Calculator
Work out testosterone-to-oestradiol and progesterone-to-oestradiol ratios from lab values, with units converted to match.
Open Hormone Ratio Calculator →Hydroxychloroquine Dose Calculator
Work out the weight-based maximum daily hydroxychloroquine dose for lupus and rheumatoid arthritis, capped at 400 mg.
Open Hydroxychloroquine Dose Calculator →Ibuprofen Dosage Calculator
Check published ibuprofen single doses and daily maxima for adults and weight-based doses for children, from labelling only.
Open Ibuprofen Dosage Calculator →Ideal Body Weight Calculator
Compare ideal body weight from the Devine, Robinson and Hamwi formulas for a given height and sex.
Open Ideal Body Weight Calculator →Implantation Date Calculator
Estimate the implantation window — 6 to 12 days after ovulation or conception — with the most likely day in the middle.
Open Implantation Date Calculator →Incidence Rate Calculator
Calculate incidence rate from new cases and person-time, expressed per 1,000, 10,000 or 100,000 person-years.
Open Incidence Rate Calculator →Injury Severity Score Calculator
Score trauma severity with the Injury Severity Score — the sum of squares of the three worst AIS body-region scores.
Open Injury Severity Score Calculator →Insulin Dosage Calculator
Estimate a starting total daily insulin dose from body weight, with basal–bolus split, carb ratio and correction factor, for clinician review.
Open Insulin Dosage Calculator →Insulin Resistance Calculator
Work out insulin resistance from fasting glucose and insulin with both HOMA-IR and QUICKI, the two standard indices.
Open Insulin Resistance Calculator →Intracerebral Hemorrhage Score Calculator
Score intracerebral haemorrhage severity with the published ICH Score and its 30-day mortality by score.
Open Intracerebral Hemorrhage Score Calculator →IQ Percentile Calculator
Convert an IQ score to its percentile rank on the normal distribution, with the standard classification band.
Open IQ Percentile Calculator →Iron Deficiency Calculator
Estimate total body iron deficit with the Ganzoni formula from weight, haemoglobin and a target haemoglobin.
Open Iron Deficiency Calculator →Isotretinoin Dosage Calculator
Work out a weight-based isotretinoin daily dose and cumulative dose target from published dosing ranges.
Open Isotretinoin Dosage Calculator →IV Drip Rate Calculator
Convert an IV infusion into mL per hour and drops per minute for any standard drop factor.
Open IV Drip Rate Calculator →IVIG Dose Calculator
Calculate total and per-day IV immunoglobulin grams from body weight and a prescribed g/kg regimen.
Open IVIG Dose Calculator →Keto Calculator
Estimate daily calories from the Mifflin-St Jeor equation and split them into keto fat, protein and carbohydrate grams.
Open Keto Calculator →Kidney Failure Risk Calculator
Estimate 2-year and 5-year kidney failure risk with the published 4-variable KFRE from age, sex, eGFR and ACR.
Open Kidney Failure Risk Calculator →Kt/V Dialysis Calculator
Calculate single-pool Kt/V dialysis adequacy with the Daugirdas second-generation formula.
Open Kt/V Dialysis Calculator →Levothyroxine Dosage Calculator
Estimate a weight-based levothyroxine daily dose from the standard 1.6 micrograms/kg/day replacement guide.
Open Levothyroxine Dosage Calculator →Lidocaine Dose Calculator
Find the maximum safe lidocaine dose and volume from weight, epinephrine use and solution strength.
Open Lidocaine Dose Calculator →Light’s Criteria Calculator
Apply Light’s criteria to pleural and serum protein and LDH values to classify an effusion as exudate or transudate.
Open Light’s Criteria Calculator →Lille Score Calculator
Score corticosteroid response in severe alcoholic hepatitis with the published Lille model.
Open Lille Score Calculator →Local Anesthetic Dose Calculator
Compare maximum doses and volumes across lidocaine, bupivacaine, ropivacaine and prilocaine, with or without epinephrine.
Open Local Anesthetic Dose Calculator →LRINEC Score Calculator
Score necrotising fasciitis risk with the published LRINEC laboratory table.
Open LRINEC Score Calculator →Lung Capacity Calculator
Derive inspiratory capacity, vital capacity, functional residual capacity and total lung capacity from measured lung volumes.
Open Lung Capacity Calculator →Lung Nodule Growth Rate Calculator
Calculate lung nodule volume doubling time from two diameter measurements and the time between scans.
Open Lung Nodule Growth Rate Calculator →LV Mass Index Calculator
Calculate left ventricular mass and mass index with the Devereux formula and Du Bois body surface area.
Open LV Mass Index Calculator →Maddrey Discriminant Function Calculator
Score alcoholic hepatitis severity with the Maddrey discriminant function from prothrombin time and bilirubin.
Open Maddrey Discriminant Function Calculator →Mean Airway Pressure Calculator
Calculate mean airway pressure from peak pressure, PEEP and inspiratory and expiratory times.
Open Mean Airway Pressure Calculator →Mean Sac Diameter Calculator
Average three gestational sac diameters and estimate gestational age from the mean sac diameter.
Open Mean Sac Diameter Calculator →Medication Schedule Calculator
Space daily medicine doses evenly from a first-dose time, including the classic 3-times-a-day 8-hour schedule.
Open Medication Schedule Calculator →Melatonin Dosage Calculator
Check published melatonin dose ranges and timing for adults by purpose, with a clear start-low guide.
Open Melatonin Dosage Calculator →MELD Score Calculator
Calculate the classic MELD score for end-stage liver disease from bilirubin, INR, creatinine and dialysis status.
Open MELD Score Calculator →Mentzer Index Calculator
Divide MCV by red cell count to distinguish iron deficiency from thalassemia trait patterns in microcytic anaemia.
Open Mentzer Index Calculator →MET Minutes Per Week Calculator
Turn any activity into weekly MET-minutes and see how it compares with the 600 MET-minutes weekly activity target.
Open MET Minutes Per Week Calculator →Metabolic Syndrome Calculator
Check the five ATP III metabolic syndrome criteria from waist, triglycerides, HDL, blood pressure and fasting glucose.
Open Metabolic Syndrome Calculator →Metastatic Prostate Cancer Prognosis Calculator
Classify metastatic prostate cancer disease volume by the published CHAARTED definition, with population context only.
Open Metastatic Prostate Cancer Prognosis Calculator →MEWS Score Calculator
Score the Modified Early Warning Score from respiratory rate, heart rate, blood pressure, temperature and consciousness.
Open MEWS Score Calculator →Micronutrient Calculator
Compare a daily micronutrient intake with its recommended dietary allowance and check it against the tolerable upper level.
Open Micronutrient Calculator →Middle Cerebral Artery Doppler Calculator
Convert a fetal middle cerebral artery peak systolic velocity into multiples of the median using the Mari formula.
Open Middle Cerebral Artery Doppler Calculator →MIPI Score Calculator
Score the Mantle Cell Lymphoma International Prognostic Index from age, performance status, LDH and white cell count.
Open MIPI Score Calculator →Morphine Milligram Equivalent Calculator
Convert a total daily opioid dose into morphine milligram equivalents per day using the CDC 2022 factors.
Open Morphine Milligram Equivalent Calculator →Morse Fall Scale Calculator
Score the Morse Fall Scale from fall history, diagnoses, walking aid, IV therapy, gait and mental status.
Open Morse Fall Scale Calculator →Mortality Rate Calculator
Work out a crude mortality rate per 1,000 and per 100,000 people from deaths and population size.
Open Mortality Rate Calculator →NAFLD Fibrosis Score Calculator
Score liver fibrosis risk in non-alcoholic fatty liver disease from age, BMI, diabetes, AST, ALT, platelets and albumin.
Open NAFLD Fibrosis Score Calculator →NEDOCS Score Calculator
Score emergency department overcrowding with the NEDOCS formula from patients, beds, admissions and waiting times.
Open NEDOCS Score Calculator →Net Carbs Calculator
Work out net carbs by subtracting fibre and sugar alcohols from total carbohydrates for a food or meal.
Open Net Carbs Calculator →Neutrophil Lymphocyte Ratio Calculator
Divide the neutrophil count by the lymphocyte count to get the neutrophil-to-lymphocyte ratio, a general inflammation marker.
Open Neutrophil Lymphocyte Ratio Calculator →Newborn Hyperbilirubinemia Calculator
Convert a newborn bilirubin level, tally jaundice risk factors and flag urgent-review signs, for education only.
Open Newborn Hyperbilirubinemia Calculator →NIH Stroke Scale Calculator
Score all 15 items of the NIH Stroke Scale and total them into a stroke severity band.
Open NIH Stroke Scale Calculator →Noise Exposure Calculator
Work out OSHA noise dose and time-weighted average from one or two noise exposures in a shift.
Open Noise Exposure Calculator →Nuchal Translucency Calculator
Interpret a first-trimester nuchal translucency measurement with crown-rump length and estimated gestation.
Open Nuchal Translucency Calculator →Number Needed to Treat Calculator
Turn trial event rates into absolute risk reduction, relative risk reduction and the number needed to treat.
Open Number Needed to Treat Calculator →Osteoporosis Risk Score Calculator
Score osteoporosis risk with the OSTA index from age and body weight for postmenopausal women.
Open Osteoporosis Risk Score Calculator →Oxygen Tank Duration Calculator
Estimate how long an oxygen cylinder lasts at a given flow rate from its size and gauge pressure.
Open Oxygen Tank Duration Calculator →Oxygenation Index Calculator
Work out the oxygenation index from inspired oxygen fraction, mean airway pressure and arterial oxygen.
Open Oxygenation Index Calculator →Pack Years Calculator
Turn cigarettes per day and years smoked into pack-years, the standard lifetime smoking exposure measure.
Open Pack Years Calculator →Padua Score Calculator
Score venous thromboembolism risk in hospitalised medical patients with the 11-item Padua Prediction Score.
Open Padua Score Calculator →PaO2/FiO2 Ratio Calculator
Calculate the PaO2/FiO2 (P/F) ratio from arterial oxygen and inspired oxygen fraction, with the Berlin ARDS severity bands.
Open PaO2/FiO2 Ratio Calculator →Parkland Formula Calculator
Calculate Parkland burn resuscitation fluids: 4 mL per kg per percent burn, half in the first 8 hours and half over the next 16.
Open Parkland Formula Calculator →Peak Flow Calculator
Compare a peak expiratory flow reading with a personal best and find the green, yellow or red asthma action-plan zone.
Open Peak Flow Calculator →Pearl Index Calculator
Calculate the Pearl Index — pregnancies per 100 woman-years of contraceptive use — from study or clinic data.
Open Pearl Index Calculator →PECARN Rule Calculator
Apply the PECARN paediatric head-injury rule to estimate CT need after minor blunt head trauma, by age group.
Open PECARN Rule Calculator →Pediatric Blood Pressure Calculator
Screen a child’s blood pressure against the AAP simplified screening values by age and sex, and flag readings needing further evaluation.
Open Pediatric Blood Pressure Calculator →Pediatric Epinephrine Dose Calculator
Calculate weight-based paediatric epinephrine doses from PALS: IV/IO for cardiac arrest and IM for anaphylaxis, with auto-injector guidance.
Open Pediatric Epinephrine Dose Calculator →Pediatric Maintenance Fluids Calculator
Calculate paediatric maintenance fluids by the Holliday-Segar 4-2-1 rule, with an optional dehydration deficit estimate.
Open Pediatric Maintenance Fluids Calculator →Pediatric Transfusion Calculator
Estimate paediatric packed red cell volume from weight and the haemoglobin rise wanted, at 3 mL/kg per 1 g/dL.
Open Pediatric Transfusion Calculator →PERC Rule Calculator
Apply the eight PERC criteria to see whether pulmonary embolism can be ruled out in a low-risk patient without further testing.
Open PERC Rule Calculator →PHQ-9 Depression Screening Calculator
Score the nine PHQ-9 depression questions, with severity bands and a flag for any thoughts of self-harm.
Open PHQ-9 Depression Screening Calculator →PISA Radius Calculator
Calculate the effective regurgitant orifice area from the PISA flow-convergence radius, aliasing velocity and peak jet velocity.
Open PISA Radius Calculator →Pneumonia Severity Index Calculator
Score the Pneumonia Severity Index (PORT score) from age, comorbidity, vitals and labs, with risk classes I to V.
Open Pneumonia Severity Index Calculator →Ponderal Index Calculator
Calculate the ponderal (Rohrer) index from weight and height, with the body-mass index shown for context.
Open Ponderal Index Calculator →Pregnancy Test Timing Calculator
Find the earliest sensible pregnancy-test date from ovulation and test sensitivity, plus the missed-period date and an hCG doubling check.
Open Pregnancy Test Timing Calculator →Pregnancy Weight Gain Calculator
Check pregnancy weight gain against the Institute of Medicine ranges by pre-pregnancy BMI, with expected gain for the current week.
Open Pregnancy Weight Gain Calculator →Prescription Refill Date Calculator
Work out when a prescription runs out, when the next refill is due, and when the remaining refills are exhausted.
Open Prescription Refill Date Calculator →Prostate Volume Calculator
Calculate prostate volume by the ellipsoid formula from ultrasound dimensions, with PSA density when PSA is entered.
Open Prostate Volume Calculator →Protein-Creatinine Ratio Calculator
Convert a spot urine protein-creatinine ratio into g/g and mg/mmol, with the normal, elevated and nephrotic-range bands.
Open Protein-Creatinine Ratio Calculator →PSA Calculator
Interpret total PSA with age-adjusted ranges, free-PSA percentage, PSA density and PSA velocity in one place.
Open PSA Calculator →Pulmonary Vascular Resistance Calculator
Calculate pulmonary vascular resistance in Wood units and dyn·s·cm⁻⁵ from mean pulmonary artery pressure, wedge pressure and cardiac output.
Open Pulmonary Vascular Resistance Calculator →Qp/Qs Ratio Calculator
Calculate the pulmonary-to-systemic flow ratio (Qp/Qs) from oxygen saturations to size a cardiac shunt.
Open Qp/Qs Ratio Calculator →qSOFA Score Calculator
Score qSOFA from respiratory rate, systolic blood pressure and Glasgow Coma Scale to flag sepsis risk outside intensive care.
Open qSOFA Score Calculator →QTc Calculator
Correct the QT interval for heart rate by both the Bazett and Fridericia formulas, with sex-based prolongation flags.
Open QTc Calculator →Quit Smoking Calculator
See how much money you save and how many cigarettes you avoid after quitting smoking, with a life-regained illustration.
Open Quit Smoking Calculator →Race Time Predictor
Predict your finish time for any race distance from a known race result using the Riegel formula.
Open Race Time Predictor →Radiation Dose Calculator
Add up typical effective radiation doses from X-rays and CT scans and compare them with yearly background radiation.
Open Radiation Dose Calculator →Rapid Shallow Breathing Index Calculator
Calculate the rapid shallow breathing index from respiratory rate and tidal volume as a weaning aid.
Open Rapid Shallow Breathing Index Calculator →Rate Pressure Product Calculator
Multiply heart rate by systolic pressure to estimate myocardial oxygen demand at rest or exercise.
Open Rate Pressure Product Calculator →RBC Indices Calculator
Calculate MCV, MCH and MCHC from haemoglobin, haematocrit and red cell count, with a cell classification.
Open RBC Indices Calculator →Relative Fat Mass (RFM) Calculator
Estimate whole-body fat percentage from height and waist circumference with the Woolcott and Bergman formula.
Open Relative Fat Mass (RFM) Calculator →REM Sleep Calculator
Find bedtimes that let you wake at the end of a 90-minute sleep cycle, for 4, 5 or 6 cycles.
Open REM Sleep Calculator →Reticulocyte Count Calculator
Correct the reticulocyte count for anaemia and calculate the reticulocyte production index.
Open Reticulocyte Count Calculator →Reverse Due Date Calculator
Work backwards from an expected due date to an estimated last period start and conception date.
Open Reverse Due Date Calculator →Revised Cardiac Risk Index Calculator
Count the six Lee risk factors to estimate major cardiac complications after major non-cardiac surgery.
Open Revised Cardiac Risk Index Calculator →Revised Geneva Score Calculator
Score suspected pulmonary embolism probability with the Revised Geneva rule from history, symptoms and heart rate.
Open Revised Geneva Score Calculator →Revised Trauma Score Calculator
Calculate the Revised Trauma Score from coded Glasgow Coma Scale, systolic pressure and respiratory rate.
Open Revised Trauma Score Calculator →SAAG Calculator
Calculate the serum-ascites albumin gradient to separate portal-hypertensive from other causes of ascites.
Open SAAG Calculator →Salad Calories Calculator
Build a salad from ingredient weights and total its calories and protein from typical nutrition values.
Open Salad Calories Calculator →SAPS II Score Calculator
Calculate the SAPS II severity score and estimated hospital mortality from first-24-hour ICU values.
Open SAPS II Score Calculator →SCORAD Calculator
Score atopic dermatitis severity from extent, six intensity signs, itch and sleep loss with the SCORAD formula.
Open SCORAD Calculator →Sepsis Screening Calculator
Screen for possible sepsis with qSOFA and SIRS counts and get clear urgent-care direction. Screening aid only.
Open Sepsis Screening Calculator →Serum Osmolality Calculator
Calculate serum osmolality from sodium, glucose and BUN, with the osmolar gap when a measured value is known.
Open Serum Osmolality Calculator →Shock Index Calculator
Calculate shock index and modified shock index from heart rate and blood pressure as an early shock flag.
Open Shock Index Calculator →SIR Epidemic Model Calculator
Run an educational SIR epidemic model with your own transmission and recovery rates and see the peak and final size.
Open SIR Epidemic Model Calculator →Sleep Debt Calculator
Add up the gap between ideal and actual sleep over several nights and plan a gentle repayment.
Open Sleep Debt Calculator →Smoking Recovery Calculator
Track recovery milestones after quitting smoking, from the first 20 minutes to 15 years smoke-free.
Open Smoking Recovery Calculator →SNAP Score Calculator
Calculate the neonatal SNAP-II severity score from six first-12-hour NICU items with published point weights.
Open SNAP Score Calculator →Sobriety Calculator
Count days sober and total the money saved, drinks avoided and calories avoided since quitting alcohol.
Open Sobriety Calculator →Sodium Correction Calculator
Correct serum sodium for high blood glucose with the Katz formula, and estimate how one litre of IV fluid would move sodium using the Adrogué–Madias equation.
Open Sodium Correction Calculator →SOFA Score Calculator
Score organ dysfunction across respiration, coagulation, liver, cardiovascular, nervous system and kidneys with the Sequential Organ Failure Assessment (SOFA) table.
Open SOFA Score Calculator →Sperm Analysis Calculator
Check a semen analysis against the WHO 2021 reference limits: volume, concentration, total count, motility, vitality and morphology.
Open Sperm Analysis Calculator →Sports Drink Calculator
Work out your sweat rate from before-and-after weights, then get a fluid, sodium and carbohydrate plan for training or racing.
Open Sports Drink Calculator →STOP-Bang Sleep Apnea Screening Calculator
Answer the eight STOP-Bang questions to screen for obstructive sleep apnea risk — snoring, tiredness, observed apnea, blood pressure, BMI, age, neck size and sex.
Open STOP-Bang Sleep Apnea Screening Calculator →Stride Length Calculator
Estimate stride length from height, or measure it exactly from a known distance and step count — and convert it to steps per kilometre and per mile.
Open Stride Length Calculator →Stroke Volume Calculator
Calculate stroke volume from end-diastolic and end-systolic volumes, from cardiac output and heart rate, or from the LVOT diameter and velocity–time integral.
Open Stroke Volume Calculator →Sunscreen Amount Calculator
Find how much sunscreen you actually need: the dermatology standard is 2 mg per square centimetre of skin, which is far more than most people apply.
Open Sunscreen Amount Calculator →Sunscreen Calculator
Estimate how long you can stay in the sun with sunscreen: your skin type sets your unprotected burn time, the UV index scales it, and SPF multiplies it.
Open Sunscreen Calculator →Swimming Time Calculator
Turn a swim distance and pace into a finish time, with speed, splits and an energy estimate — for pool sets and open-water swims alike.
Open Swimming Time Calculator →Thanksgiving Calories Calculator
Build your Thanksgiving plate serving by serving — turkey, stuffing, sides, gravy, pie and drinks — and see the total, its share of a day, and the walk to burn it off.
Open Thanksgiving Calories Calculator →TI-RADS Calculator
Score a thyroid nodule with the ACR TI-RADS system: composition, echogenicity, shape, margin and echogenic foci give a TR level and a follow-up or biopsy recommendation.
Open TI-RADS Calculator →Tidal Volume Calculator
Set a lung-protective tidal volume from predicted body weight (Devine formula): enter height and sex, pick 6–8 mL/kg, and get the volume plus minute ventilation.
Open Tidal Volume Calculator →Time of Death Estimator
An educational postmortem-interval estimator based on body cooling (the Glaister equation): enter body temperature and see a rough hours-since-death figure with its wide uncertainty.
Open Time of Death Estimator →TIMI STEMI Score Calculator
Score 30-day mortality risk in ST-elevation MI with the TIMI STEMI score: eight admission variables, 0–14 points, each tied to a published mortality rate.
Open TIMI STEMI Score Calculator →TIMI UA/NSTEMI Score Calculator
Score 14-day risk of death, MI or urgent revascularisation in unstable angina and NSTEMI with the seven-point TIMI UA/NSTEMI score.
Open TIMI UA/NSTEMI Score Calculator →Tinetti Assessment Calculator
Score the full Tinetti Performance Oriented Mobility Assessment: nine balance items (0–16) and ten gait items (0–12) combine into a 0–28 fall-risk score.
Open Tinetti Assessment Calculator →tPA Dosing Calculator
Calculate the standard alteplase (tPA) dose for acute ischemic stroke: 0.9 mg/kg up to 90 mg, with 10% as a bolus and the rest infused over 60 minutes.
Open tPA Dosing Calculator →Tramadol Dosage Calculator
Check an adult tramadol regimen against published dosing: immediate-release 50–100 mg every 4–6 hours (max 400 mg/day) or extended-release 100–300 mg once daily.
Open Tramadol Dosage Calculator →Transferrin Saturation Calculator
Calculate transferrin saturation (TSAT) from serum iron and total iron-binding capacity, with unsaturated iron-binding capacity and an iron-status band.
Open Transferrin Saturation Calculator →Triathlon Time Calculator
Add up a triathlon finish time from swim, bike and run legs plus both transitions, with per-leg paces for Sprint, Olympic, 70.3 and Ironman distances.
Open Triathlon Time Calculator →TTKG Calculator
Calculate the transtubular potassium gradient (TTKG) from urine and plasma potassium and osmolality, to help separate renal from non-renal causes of potassium disorders.
Open TTKG Calculator →Twin Probability Calculator
A rough, educational estimate of twin-pregnancy probability from conception method, maternal age, family history, previous twins and BMI — not a personal prediction.
Open Twin Probability Calculator →Urea Reduction Ratio Calculator
Measure dialysis adequacy with the urea reduction ratio, and add single-pool Kt/V by the Daugirdas equation when session length, ultrafiltration and post-dialysis weight are known.
Open Urea Reduction Ratio Calculator →Urine Output Calculator
Work out urine output in mL per kg per hour from total volume, collection time and body weight, with the usual adult range.
Open Urine Output Calculator →Vaccine Efficacy Calculator
Calculate vaccine efficacy from case counts in vaccinated and unvaccinated groups, with attack rates for both groups.
Open Vaccine Efficacy Calculator →Vaccine Immunity Calculator
Model how vaccine effectiveness fades over time with a transparent exponential-waning model you can adjust, clearly labelled as educational only.
Open Vaccine Immunity Calculator →VBAC Risk Score Calculator
Estimate the chance of a successful vaginal birth after caesarean with the Grobman 2021 refit model, which uses no race or ethnicity terms.
Open VBAC Risk Score Calculator →Vitamin A Intake Calculator
Add up vitamin A from food and supplements in mcg RAE, compare it with the RDA for your group and flag the upper level.
Open Vitamin A Intake Calculator →Vitamin D Intake Calculator
Add up vitamin D from food and supplements in IU and mcg, compare it with the RDA for your age group and flag the upper level.
Open Vitamin D Intake Calculator →VLDL Cholesterol Calculator
Estimate VLDL cholesterol from triglycerides with the Friedewald equation, in mg/dL or mmol/L, with the usual range.
Open VLDL Cholesterol Calculator →VTE Risk in Pregnancy Calculator
Count venous thromboembolism risk factors in pregnancy into a low, intermediate or high band, as an educational triage aid for clinician discussion.
Open VTE Risk in Pregnancy Calculator →Waist-to-Height Ratio Calculator
Divide waist by height for a shape-based health indicator, with the widely used 0.5 cut-off and unit switching between cm and inches.
Open Waist-to-Height Ratio Calculator →Waist-to-Hip Ratio Calculator
Divide waist by hip circumference and compare it with the WHO high-risk cut-offs for men and women, with cm/inch switching.
Open Waist-to-Hip Ratio Calculator →Warfarin Dosing Calculator
Adjust a stable weekly warfarin dose from the latest INR using the published maintenance table for target INR 2.0 to 3.0, for prescriber discussion only.
Open Warfarin Dosing Calculator →Weighted Blanket Calculator
Find the recommended weighted blanket weight from body weight using the common 10% guideline, with a 7 to 12% range.
Open Weighted Blanket Calculator →Wells PE Score Calculator
Score pulmonary embolism probability with the published Wells criteria, in both the three-tier and the simplified two-tier forms.
Open Wells PE Score Calculator →Wilks Calculator
Compute the classic Wilks coefficient and Wilks score from body weight and total lifted, for men and women.
Open Wilks Calculator →Winters Formula Calculator
Check respiratory compensation in metabolic acidosis with Winters formula, comparing measured pCO2 with the expected range.
Open Winters Formula Calculator →Cursive Font Generator
Turn plain text into elegant cursive script characters you can copy into bios, posts and messages.
Open Cursive Font Generator →Fancy Text Generator
Style text in six fancy Unicode styles, from bold and italic to script, double-struck, monospace and circled.
Open Fancy Text Generator →Glitch Text Generator
Add deterministic Zalgo-style combining marks above and below your text for a glitch effect, in light, medium or heavy intensity.
Open Glitch Text Generator →Italic Text Generator
Turn plain text into mathematical italic characters for bios, posts and messages, with one-click copy.
Open Italic Text Generator →Reverse Text Generator
Reverse any text character by character, safely handling emoji and accented characters, with one-click copy.
Open Reverse Text Generator →Underline Text Generator
Add a Unicode combining underline to every character of your text, so it stays underlined when pasted anywhere.
Open Underline Text Generator →Upside-Down Text Generator
Flip text upside down with a Unicode flip map and reverse it, so it reads when you turn it over, with one-click copy.
Open Upside-Down Text Generator →Yes or No Generator
Ask a yes-or-no question and get a random Yes or No answer, with a fresh draw on every tap.
Open Yes or No Generator →3D Printing Calculator
Estimate 3D print time, filament weight and length, and material cost from model volume, infill, layer height, speed and material.
Open 3D Printing Calculator →3D Render Time Calculator
Estimate total 3D render time from frame count, seconds per frame and render nodes, with overhead and cost.
Open 3D Render Time Calculator →A/B Test Calculator
Compare two conversion rates with a two-proportion z-test, uplift, confidence and a two-tailed p-value.
Open A/B Test Calculator →Absolute Value Calculator
Find the absolute value of any number, its sign, and its distance from zero, plus the distance between two numbers.
Open Absolute Value Calculator →Absolute Value Equation Calculator
Solve equations of the form |ax + b| = c, with both cases worked and each solution checked.
Open Absolute Value Equation Calculator →Acceptance Rate Calculator
Turn applications and acceptances into an acceptance rate, rejection rate and one-in-N odds.
Open Acceptance Rate Calculator →ACT Score Calculator
Average your four ACT section scores into a composite, rounded exactly the way ACT rounds it.
Open ACT Score Calculator →Activation Energy Calculator
Find activation energy from two rate constants at two temperatures with the two-point Arrhenius equation.
Open Activation Energy Calculator →Activity Coefficient Calculator
Estimate a single-ion activity coefficient in water at 25 C with the extended Debye-Huckel equation.
Open Activity Coefficient Calculator →AI Job Risk Calculator
Score a job’s exposure to AI automation from five transparent factors — an educational estimate, never a prediction.
Open AI Job Risk Calculator →Air Fuel Ratio Calculator
Compute air-fuel ratio and lambda from air and fuel mass, against the stoichiometric ratio for your fuel.
Open Air Fuel Ratio Calculator →Alligation Calculator
Blend two strengths to a target strength with the alligation method: parts of each and quantities for any total.
Open Alligation Calculator →Amdahl’s Law Calculator
Estimate program speedup from the parallel fraction and processor speedup, with the theoretical maximum.
Open Amdahl’s Law Calculator →Ancient Numeral Converter
Convert a decimal number to Mayan vigesimal numerals and Roman numerals, with the place values shown.
Open Ancient Numeral Converter →Angle of Impact Calculator
Find a bloodstain’s angle of impact from its width and length with the arcsine method.
Open Angle of Impact Calculator →ANOVA Calculator
Run a one-way ANOVA on up to four groups: F statistic, p-value from the F distribution, and group means.
Open ANOVA Calculator →Antipode Calculator
Find the exact opposite point on Earth for any latitude and longitude, plus the antipodal distance.
Open Antipode Calculator →AP Score Calculator
Estimate an AP score from multiple-choice and free-response percentages — a clearly labelled generic estimator, not a College Board score.
Open AP Score Calculator →Appliance Wattage Calculator
Work out an appliance’s wattage from volts and amps, or from a typical preset, plus daily energy use.
Open Appliance Wattage Calculator →Aquarium Glass Thickness Calculator
Estimate aquarium glass thickness from tank height and length with a conservative plate calculation, rounded up to a standard size.
Open Aquarium Glass Thickness Calculator →Arithmetic Sequence Calculator
Find any term and the sum of an arithmetic sequence from the first term, common difference and term count.
Open Arithmetic Sequence Calculator →Arrhenius Equation Calculator
Compute a reaction rate constant from the pre-exponential factor, activation energy and temperature.
Open Arrhenius Equation Calculator →Arrow FOC Calculator
Find an arrow’s front-of-center percentage from total length and balance point, with a tuning guide.
Open Arrow FOC Calculator →Atom Economy Calculator
Measure how much reactant mass ends up in the desired product, plus waste mass and the E-factor.
Open Atom Economy Calculator →Audio File Size Calculator
Estimate audio file size from sample rate, bit depth, channels and duration, or from a compressed bitrate.
Open Audio File Size Calculator →Azimuth Calculator
Find the initial bearing and great-circle distance between two points from their latitudes and longitudes.
Open Azimuth Calculator →Balloon Arch Calculator
Work out how many balloons, clusters and helium you need for a balloon arch from its width, height and balloon size.
Open Balloon Arch Calculator →Bandwidth Calculator
Find the internet speed you need to transfer a file in a given time, or how long a transfer takes at a given speed.
Open Bandwidth Calculator →Baseball Game Score Calculator
Score a pitcher’s start with the published Bill James Game Score formula, from outs, strikeouts, hits, runs and walks.
Open Baseball Game Score Calculator →Baseball Stats Calculator
Calculate batting average, on-base percentage, slugging and OPS from at-bats, hits, extra-base hits, walks and hit-by-pitches.
Open Baseball Stats Calculator →Baseball WAR Calculator
Estimate a batter’s WAR with a clearly labelled simplified wOBA model — an approximation, not an official Baseball-Reference or FanGraphs figure.
Open Baseball WAR Calculator →Bathroom Mirror Size Calculator
Find a recommended bathroom mirror width and height from your vanity width, using the standard 70–80% of vanity width guide.
Open Bathroom Mirror Size Calculator →Battery Charge Time Calculator
Estimate how long a battery takes to charge from its capacity, charger power and charging efficiency.
Open Battery Charge Time Calculator →Batting Strike Rate Calculator
Calculate a cricket batter’s strike rate from runs scored and balls faced, with boundary share included.
Open Batting Strike Rate Calculator →Bayes’ Theorem Calculator
Update a probability with new evidence using Bayes’ theorem, from a prior, a true-positive rate and a false-positive rate.
Open Bayes’ Theorem Calculator →Bean Bag Filling Calculator
Work out how much bean bag filling you need from the bag’s size and shape, in litres, bags and weight.
Open Bean Bag Filling Calculator →Bed Size Calculator
Pick a bed size from standard dimensions using sleepers, sleeper height and room size, with a walkway clearance check.
Open Bed Size Calculator →Beer-Lambert Law Calculator
Calculate absorbance and transmittance from molar absorptivity, path length and concentration with the Beer-Lambert law.
Open Beer-Lambert Law Calculator →Belt Size Calculator
Convert waist size to belt size with the standard waist-plus-two-inches guide, in inches and centimetres.
Open Belt Size Calculator →Benford’s Law Calculator
Test first-digit counts against Benford’s law, with expected frequencies, chi-square, MAD and a conformity verdict.
Open Benford’s Law Calculator →Beta Distribution Calculator
Calculate the beta distribution PDF, CDF, mean and variance from shape parameters alpha and beta at a value x.
Open Beta Distribution Calculator →Bike Chain Length Calculator
Calculate bicycle chain length in links from chainstay length, chainring and rear cog sizes, using the standard chain-length formula.
Open Bike Chain Length Calculator →Bike Gear Calculator
Calculate gear inches, gear ratio, development and speed from chainring, cog, wheel size and cadence.
Open Bike Gear Calculator →Bike Size Calculator
Estimate bicycle frame size from height and inseam, for road, hybrid and mountain bikes, using standard inseam formulas.
Open Bike Size Calculator →Birthday Paradox Calculator
Calculate the probability that two people in a group share a birthday, the famous birthday paradox.
Open Birthday Paradox Calculator →Bitwise Calculator
Perform bitwise AND, OR, XOR, NOT, NAND, NOR and shifts on integers, with decimal, binary and hexadecimal results.
Open Bitwise Calculator →Blind Size Calculator
Work out the blind size to order for inside or outside mounting, from window recess width and height, using standard fitting guides.
Open Blind Size Calculator →Boiling Point Altitude Calculator
Find the boiling point of water at altitude, from atmospheric pressure by the barometric formula and the Antoine equation.
Open Boiling Point Altitude Calculator →Boiling Point Calculator
Find the boiling point of water at any pressure with the Antoine equation, in Celsius and Fahrenheit.
Open Boiling Point Calculator →Boiling Point Elevation Calculator
Calculate boiling-point elevation from solute mass, molar mass, solvent mass and the van’t Hoff factor.
Open Boiling Point Elevation Calculator →Bond Order Calculator
Calculate bond order from bonding and antibonding electrons with molecular orbital theory, with bond type and stability.
Open Bond Order Calculator →Bonferroni Correction Calculator
Divide your significance level by the number of tests to control the family-wise error rate, with the adjusted p-value and Šidák comparison.
Open Bonferroni Correction Calculator →Bowling Average Calculator
Work out a bowler’s average, economy rate and strike rate from runs conceded, wickets taken and balls bowled.
Open Bowling Average Calculator →Box Plot Generator
Turn a list of numbers into a five-number summary — minimum, quartiles, median and maximum — with outliers flagged.
Open Box Plot Generator →Brake Specific Fuel Consumption Calculator
Convert fuel flow and brake power into brake specific fuel consumption in g/kWh, with thermal efficiency for common fuels.
Open Brake Specific Fuel Consumption Calculator →Buffer Capacity Calculator
Calculate buffer capacity in mol/L per pH unit from total buffer concentration, pKa and pH.
Open Buffer Capacity Calculator →Buffer pH Calculator
Find buffer pH from pKa and the acid and conjugate-base concentrations using the Henderson–Hasselbalch equation.
Open Buffer pH Calculator →Calibration Curve Calculator
Fit a linear calibration curve to standard concentrations and responses, then read unknown samples and detection limits.
Open Calibration Curve Calculator →Carbon Dating Calculator
Estimate the age of organic material from its remaining carbon-14, or the remaining fraction from an age, using the 5,730-year half-life.
Open Carbon Dating Calculator →Catenary Curve Calculator
Evaluate a catenary curve y = a·cosh(x/a), or find the curve through a given span and sag, with arc length and slope.
Open Catenary Curve Calculator →CBM Shipping Calculator
Convert carton dimensions into cubic metres (CBM), total volume and volumetric weight for air or sea freight.
Open CBM Shipping Calculator →Ceiling and Floor Functions Calculator
Evaluate ceiling, floor, truncation and rounding for any number, including negative values where the functions differ.
Open Ceiling and Floor Functions Calculator →Chebyshev’s Theorem Calculator
Apply Chebyshev’s theorem: find the interval within k standard deviations and the minimum percentage of data it must contain.
Open Chebyshev’s Theorem Calculator →Chemical Equation Balancer
Balance chemical equations with a real rational null-space algorithm — enter reactants and products and get integer coefficients.
Open Chemical Equation Balancer →Chemical Name Calculator
Look up the common name of a familiar chemical formula from a clearly labelled table of common compounds — no invented systematic names.
Open Chemical Name Calculator →Chemical Oxygen Demand Calculator
Calculate chemical oxygen demand (COD) in mg/L from a dichromate titration blank, sample titre and sample volume.
Open Chemical Oxygen Demand Calculator →Chi-Square Calculator
Run a chi-square goodness-of-fit or 2×2 independence test, with the p-value from the incomplete gamma function.
Open Chi-Square Calculator →Chinese Remainder Theorem Calculator
Solve simultaneous congruences x ≡ r (mod m) for pairwise coprime moduli, with the combined modulus and verification.
Open Chinese Remainder Theorem Calculator →Circle Equation Calculator
Convert between centre–radius and general circle equations, with area, circumference and diameter.
Open Circle Equation Calculator →Circular Sector and Segment Calculator
Find sector area, arc length, segment area, chord length and perimeter from radius and central angle.
Open Circular Sector and Segment Calculator →Classroom Spacing Calculator
Work out how many students fit a classroom at a given spacing, or the spacing a class size allows, in a grid layout.
Open Classroom Spacing Calculator →Clay Shrinkage Calculator
Measure drying, firing and total clay shrinkage from wet, dry and fired sizes, or size wet clay for a target fired size.
Open Clay Shrinkage Calculator →Clock Angle Calculator
Find the angle between the hour and minute hands for any time, including the smaller and reflex angles.
Open Clock Angle Calculator →Clothing Size Calculator
Estimate a generic letter clothing size from chest and waist measurements — a guide, not any brand’s official chart.
Open Clothing Size Calculator →Coefficient of Determination Calculator
Compute R², correlation r, slope and intercept for paired data, with an interpretation of how well the line fits.
Open Coefficient of Determination Calculator →Coefficient of Variation Calculator
Compare relative variability across data sets: coefficient of variation from mean and standard deviation, sample or population.
Open Coefficient of Variation Calculator →Coin Flip Streak Calculator
Find the exact probability of getting a run of heads in a set number of coin flips, with the no-streak probability and expected run count.
Open Coin Flip Streak Calculator →Collatz Conjecture Calculator
Follow the Collatz 3n+1 sequence from any starting number, with step count, peak value, and odd and even step counts.
Open Collatz Conjecture Calculator →Combinations with Repetition Calculator
Count combinations with repetition, ordinary combinations, and permutations with repetition from n types and r selections.
Open Combinations with Repetition Calculator →Combustion Analysis Calculator
Turn combustion analysis mass percentages into an empirical formula, with molar mass and the unaccounted remainder.
Open Combustion Analysis Calculator →Complementary and Supplementary Angles Calculator
Find the complement and supplement of any angle, or check whether two angles are complementary, supplementary, or neither.
Open Complementary and Supplementary Angles Calculator →Completing the Square Calculator
Rewrite any quadratic in vertex form by completing the square, with vertex, axis of symmetry, and roots.
Open Completing the Square Calculator →Complex Number Calculator
Add, subtract, multiply and divide complex numbers, with modulus, conjugate, and polar form for each input.
Open Complex Number Calculator →Compression Ratio Calculator
Compute engine compression ratio from bore, stroke and clearance volume, or directly from swept and clearance volumes.
Open Compression Ratio Calculator →Conditional Probability Calculator
Compute P(A|B), P(B|A), the union and the independence check from P(A), P(B) and P(A and B).
Open Conditional Probability Calculator →Cone Calculator
Find cone volume, slant height, lateral and total surface area from radius and height, in any length unit.
Open Cone Calculator →Confusion Matrix Calculator
Turn TP, FP, TN and FN into accuracy, precision, recall, specificity, F1 and Matthews correlation coefficient.
Open Confusion Matrix Calculator →Consecutive Integers Calculator
Generate a run of consecutive integers from a start value, or find the run that adds up to a given sum.
Open Consecutive Integers Calculator →Container Loading Calculator
Estimate how many boxes fit in a shipping container by trying every box orientation, with volume use and weight limits.
Open Container Loading Calculator →Control Chart Limits Calculator
Compute X-bar and R control chart limits from subgroup data using the standard A2, D3 and D4 constants.
Open Control Chart Limits Calculator →Convolution Calculator
Compute the discrete linear convolution of two sequences, with length, peak, and sum verification.
Open Convolution Calculator →Cord of Wood Calculator
Convert a stacked woodpile into full cords and face cords from its length, width and height in any unit.
Open Cord of Wood Calculator →Correlation Calculator
Compute Pearson and Spearman correlation, R squared, and the means of two paired data lists.
Open Correlation Calculator →Cosine Similarity Calculator
Measure the cosine similarity and angle between two vectors, with dot product, magnitudes and Euclidean distance.
Open Cosine Similarity Calculator →Covariance Calculator
Compute sample and population covariance for two paired lists, with means and the Pearson correlation.
Open Covariance Calculator →Cricket Follow-On Calculator
Check whether a first-innings lead is enough to enforce the follow-on under the Laws of Cricket, for any match length.
Open Cricket Follow-On Calculator →Critical Value Calculator
Find critical values for the normal, t and chi-square distributions at any significance level, verified against published tables.
Open Critical Value Calculator →Cross Stitch Calculator
Convert a cross-stitch design in stitches to finished fabric size in inches or cm, including a finishing margin.
Open Cross Stitch Calculator →Crosswind Calculator
Split any wind into crosswind and headwind components for a runway heading, in knots, mph or km/h.
Open Crosswind Calculator →Crude Protein Calculator
Convert Kjeldahl nitrogen to crude protein with the standard 6.25 factor, plus dairy and wheat factors and a custom factor.
Open Crude Protein Calculator →Cube Calculator
Find cube volume, surface area, face diagonal and space diagonal from one side length, in any unit.
Open Cube Calculator →Cubic Equation Calculator
Solve any cubic equation ax³ + bx² + cx + d = 0 for all three roots, real or complex, with the discriminant and root type.
Open Cubic Equation Calculator →Cubic Unit Cell Calculator
Atoms per cell, coordination number, atomic packing factor, atomic radius and density for simple cubic, body-centred cubic and face-centred cubic crystals.
Open Cubic Unit Cell Calculator →Curtain Size Calculator
Curtain rod length, panel width, total fabric width and cut length from your window size, fullness and number of panels.
Open Curtain Size Calculator →CV Screening Time Calculator
How long CV screening takes: total hours, time per reviewer, working days to finish, and screening cost for a hiring round.
Open CV Screening Time Calculator →Cycle Time Calculator
Cycle time per unit, hourly throughput and takt time from production time, output and customer demand.
Open Cycle Time Calculator →Cycloid Calculator
Point position, arc length and area under a cycloid from the rolling circle radius and rotation angle.
Open Cycloid Calculator →Cyclomatic Complexity Calculator
Cyclomatic complexity from a control-flow graph (edges, nodes, components) or from decision-point count, with a risk interpretation.
Open Cyclomatic Complexity Calculator →Cylinder Calculator
Volume, surface area, lateral area, base area and circumference of a cylinder from radius and height, with a hollow-cylinder option.
Open Cylinder Calculator →Cylindrical and Spherical Coordinates Calculator
Convert between Cartesian, cylindrical and spherical coordinates, with angles in degrees or radians.
Open Cylindrical and Spherical Coordinates Calculator →Data Usage Calculator
Estimate daily and monthly mobile or broadband data use from streaming, music, browsing and video calls, and how long a data plan lasts.
Open Data Usage Calculator →Dating Theory Calculator
The optimal-stopping (37%) rule for dating: how many people to meet before settling, your chance of picking the best, and how long exploring takes.
Open Dating Theory Calculator →Degree of Unsaturation Calculator
Rings plus pi bonds (index of hydrogen deficiency) from a molecular formula: carbon, hydrogen, nitrogen and halogen counts.
Open Degree of Unsaturation Calculator →Degrees Minutes Seconds Converter
Convert decimal degrees to degrees, minutes and seconds, and back again, for coordinates and angles.
Open Degrees Minutes Seconds Converter →Desk Height Calculator
Ergonomic sitting and standing desk heights, chair height and screen height from your body height.
Open Desk Height Calculator →Detention Time Calculator
Hydraulic retention (detention) time for tanks and treatment basins from volume and flow rate, in hours and days.
Open Detention Time Calculator →Diamond Carat Calculator
Convert diamond carat weight to grams and points, and estimate round-brilliant diameter from carat (or carat from diameter).
Open Diamond Carat Calculator →Diffusion Coefficient Calculator
Stokes–Einstein diffusion coefficient from temperature, solvent viscosity and particle radius, plus root-mean-square displacement.
Open Diffusion Coefficient Calculator →Dilution Ratio Calculator
Parts of concentrate and solvent for a dilution ratio like 1:10, from a total volume — for cleaning, detailing, gardening and lab dilutions.
Open Dilution Ratio Calculator →Dimensional Weight Calculator
Dimensional (volumetric) weight for parcels from length, width and height, with common carrier divisors and billable weight against actual weight.
Open Dimensional Weight Calculator →DIN Setting Calculator
Approximate ski-binding DIN setting from weight, boot sole length, skier type and age — an estimate that must be verified by a certified technician.
Open DIN Setting Calculator →Divisibility Test Calculator
Test whether a whole number is divisible by 2 through 12, with remainders, digit sum and a primality check.
Open Divisibility Test Calculator →Dot Plot Generator
Turn a list of numbers into a dot plot with counts per value, plus mean, median, mode, minimum and maximum.
Open Dot Plot Generator →DPMO Calculator
Defects per million opportunities, yield and sigma level for a process from defects, units and opportunities per unit.
Open DPMO Calculator →Drake Equation for Love Calculator
A playful estimator of how many potential partners match your criteria, from population and successive filters — an estimator, never a prediction.
Open Drake Equation for Love Calculator →Drone Flight Time Calculator
Drone flight time from battery capacity, voltage and current draw, with energy, reserve-adjusted time and range at a cruise speed.
Open Drone Flight Time Calculator →Drone Motor Calculator
Size drone motors from take-off weight, motor count and a thrust safety factor, with hover thrust and power draw.
Open Drone Motor Calculator →Duckworth Lewis Calculator
Estimate a rain-affected par score with a clearly labelled educational resource model — not official ICC Duckworth-Lewis-Stern values.
Open Duckworth Lewis Calculator →E-Bike Range Calculator
Estimate e-bike range from battery capacity, energy use and assist level, in kilometres and miles.
Open E-Bike Range Calculator →Earthquake Calculator
Convert earthquake magnitude to energy released, TNT equivalent and shaking class, from the Gutenberg-Richter energy relation.
Open Earthquake Calculator →Effect Size Calculator
Compute Cohen’s d and Hedges’ g from two group means, standard deviations and sample sizes, with interpretation.
Open Effect Size Calculator →Effective Field Goal Percentage Calculator
Calculate effective field goal percentage (eFG%) from field goals made, three-pointers made and attempts, plus true shooting.
Open Effective Field Goal Percentage Calculator →Effective Nuclear Charge Calculator
Calculate Slater’s effective nuclear charge (Zeff) for elements hydrogen to calcium, with shielding explained.
Open Effective Nuclear Charge Calculator →Egyptian Fraction Calculator
Expand a fraction into distinct unit fractions with the greedy algorithm, and verify the sum.
Open Egyptian Fraction Calculator →Eigenvalue Eigenvector Calculator
Find eigenvalues and eigenvectors for 2x2 matrices exactly, and for symmetric 3x3 matrices by Jacobi iteration.
Open Eigenvalue Eigenvector Calculator →Electrolysis Calculator
Calculate the mass deposited or liberated in electrolysis from current, time and Faraday’s law.
Open Electrolysis Calculator →Electromotive Force Calculator
Calculate cell EMF from half-cell potentials, with the Nernst equation and Gibbs free energy.
Open Electromotive Force Calculator →Electronegativity Calculator
Look up Pauling electronegativity values and classify the bond between two elements.
Open Electronegativity Calculator →Ellipse Calculator
Calculate ellipse area, perimeter (Ramanujan), eccentricity, foci and latus rectum from the two semi-axes.
Open Ellipse Calculator →Ellipsoid Volume Calculator
Calculate ellipsoid volume and Knud Thomsen surface area from the three semi-axes.
Open Ellipsoid Volume Calculator →Elo Rating Calculator
Update chess-style Elo ratings from both players’ ratings, K-factor and the game result.
Open Elo Rating Calculator →Empirical Formula Calculator
Derive an empirical formula from element masses or percentages for carbon, hydrogen, oxygen and nitrogen.
Open Empirical Formula Calculator →Engagement Rate Calculator
Calculate social media engagement rate by followers and by reach, from likes, comments, shares and saves.
Open Engagement Rate Calculator →Entropy Calculator
Calculate entropy change for reversible heat transfer and for ideal-gas expansion, in J/K.
Open Entropy Calculator →Enzyme Activity Calculator
Calculate enzyme activity in U/mL and U/L from absorbance change, volumes and extinction coefficient.
Open Enzyme Activity Calculator →Equilibrium Constant Calculator
Calculate Kc from equilibrium concentrations and stoichiometric coefficients, with reaction quotient comparison.
Open Equilibrium Constant Calculator →ERA Calculator
Calculate baseball earned run average (ERA) from earned runs and innings pitched, plus WHIP.
Open ERA Calculator →Error Propagation Calculator
Propagate measurement uncertainties through addition, subtraction, multiplication, division and powers.
Open Error Propagation Calculator →EUI Calculator
Calculate building Energy Use Intensity (EUI) from annual energy use and floor area, in kBtu/ft² and kWh/m².
Open EUI Calculator →Euler Polyhedron Formula Calculator
Check Euler’s polyhedron formula V - E + F = 2, or solve for a missing count.
Open Euler Polyhedron Formula Calculator →Exponential Distribution Calculator
Calculate exponential distribution PDF, CDF, mean, median and survival probability from the rate λ.
Open Exponential Distribution Calculator →Exponential Regression Calculator
Fit an exponential curve y = a·e^(bx) to your data, with R² and a prediction at any x.
Open Exponential Regression Calculator →Fabric Calculator
Work out how much fabric a project needs from its size, the fabric width, pattern repeat and waste allowance.
Open Fabric Calculator →Factorial Calculator
Compute n! exactly with big integers, plus trailing zeros, digit count and the Stirling approximation.
Open Factorial Calculator →Fibonacci Calculator
Find the nth Fibonacci number exactly, the sequence up to n, its sum and its approach to the golden ratio.
Open Fibonacci Calculator →FIP Calculator
Compute a pitcher’s Fielding Independent Pitching (FIP) from home runs, walks, hit batters, strikeouts and innings pitched.
Open FIP Calculator →Fish Weight Calculator
Estimate a fish’s weight from its length using published length–weight relationships for common species, with a girth-based cross-check.
Open Fish Weight Calculator →Fisher’s Exact Test Calculator
Run Fisher’s exact test on a 2×2 table, with the two-sided p-value, odds ratio and expected counts.
Open Fisher’s Exact Test Calculator →Fishing Reel Line Capacity Calculator
Convert a reel’s stated line capacity to any other line diameter, for mono and braid, in yards and metres.
Open Fishing Reel Line Capacity Calculator →Five Star Rating Calculator
Turn 1–5 star vote counts into an average rating, distribution, positive share and a Bayesian-smoothed score.
Open Five Star Rating Calculator →Freezing Point Depression Calculator
Compute freezing-point depression ΔTf = i·Kf·m from solvent, solute mass, molar mass and the van’t Hoff factor.
Open Freezing Point Depression Calculator →Freight Class Calculator
Find the NMFC freight class from shipment density, with the published density scale and a density-only disclaimer.
Open Freight Class Calculator →Fuel Injector Calculator
Size fuel injectors from horsepower, cylinder count, BSFC and duty cycle, in lb/hr and cc/min.
Open Fuel Injector Calculator →Garbage Bag Size Calculator
Find the right garbage bag size from your bin’s shape and dimensions, with width, height and gallon capacity.
Open Garbage Bag Size Calculator →Gas Oil Ratio Calculator
Mix 2-stroke fuel correctly: oil from fuel and ratio, or fuel from oil, in litres, millilitres, gallons and fluid ounces.
Open Gas Oil Ratio Calculator →Gender Wage Gap Calculator
Compute the gender pay gap from median earnings for women and men: gap percentage, cents per dollar and annual difference.
Open Gender Wage Gap Calculator →Generator Wattage Calculator
Size a generator from total running watts, the largest motor’s starting watts and a safety margin, with a recommended size.
Open Generator Wattage Calculator →Geometric & Harmonic Mean Calculator
Compute the geometric mean, harmonic mean and arithmetic mean of a list of numbers, with the ordering between them.
Open Geometric & Harmonic Mean Calculator →Geometric Distribution Calculator
Probabilities, mean and variance for the geometric distribution: trials until the first success, with success probability p.
Open Geometric Distribution Calculator →Gibbs Free Energy Calculator
Compute ΔG = ΔH − TΔS, judge spontaneity, and find the temperature where a reaction flips sign.
Open Gibbs Free Energy Calculator →Glove Size Calculator
Find your glove size from hand circumference and length, in inches and centimetres, with the size chart used.
Open Glove Size Calculator →GMAT Score Estimator
Estimate a GMAT score from section scores with a transparent, clearly-labelled model — an estimator, never an official score.
Open GMAT Score Estimator →Goalie Save Percentage Calculator
Compute a goalie’s save percentage from shots against and goals allowed, with saves, goals-against average and shutout context.
Open Goalie Save Percentage Calculator →Gradient Calculator
Convert a rise-over-run slope into gradient percentage, ratio, angle and grade — distinct from the two-point slope tool.
Open Gradient Calculator →Graham’s Law of Diffusion Calculator
Compare gas effusion and diffusion rates with Graham’s law, from molar masses, plus relative effusion times.
Open Graham’s Law of Diffusion Calculator →Great Circle Distance Calculator
Compute the shortest great-circle distance between two latitude/longitude points, with initial bearing and midpoint.
Open Great Circle Distance Calculator →GVWR Calculator
Work out your remaining payload from GVWR and curb weight, before you overload.
Open GVWR Calculator →GWA Calculator
Compute your Philippine General Weighted Average from grades and units.
Open GWA Calculator →GWAM Calculator
Compute your credit-weighted average mark (GWAM/WAM) from marks and credit points.
Open GWAM Calculator →Half Square Triangle Calculator
Cut the right starting squares for half-square triangle quilt units, two at a time.
Open Half Square Triangle Calculator →Half Life Calculator
Solve remaining quantity, elapsed time or half-life for any first-order decay.
Open Half Life Calculator →Hammock Hang Calculator
Find ridgeline length and strap height for a comfortable 30 degree hammock hang.
Open Hammock Hang Calculator →Hat Size Calculator
Turn a head measurement into US, UK and European hat sizes.
Open Hat Size Calculator →Headphone Power Calculator
Find the power, voltage and current your headphones need to reach a target loudness.
Open Headphone Power Calculator →Heat of Combustion Calculator
Compute heat released and CO2 produced when a fuel burns completely.
Open Heat of Combustion Calculator →Helium Balloons Calculator
Work out how many helium balloons it takes to lift a given weight.
Open Helium Balloons Calculator →Heptathlon Points Calculator
Score all seven women heptathlon events with the official World Athletics tables.
Open Heptathlon Points Calculator →Hexagon Quilt Calculator
Compute hexagon size, area and fabric needed for a hexagon quilt.
Open Hexagon Quilt Calculator →Hire vs Train Calculator
Compare the full cost of hiring externally against training an internal candidate.
Open Hire vs Train Calculator →Histogram Generator
Turn a list of numbers into a histogram with bin counts, mean and median.
Open Histogram Generator →Horsepower Calculator
Compute horsepower from torque and RPM, watts, work and time, or force and speed.
Open Horsepower Calculator →How Many Tables Calculator
Work out how many tables you need for your guest count and seats per table.
Open How Many Tables Calculator →Hull Speed Calculator
Find a displacement hull top efficient speed from its waterline length.
Open Hull Speed Calculator →Hyperbolic Functions Calculator
Evaluate sinh, cosh, tanh and their reciprocals for any value of x.
Open Hyperbolic Functions Calculator →Hypergeometric Distribution Calculator
Probability of drawing k successes without replacement from a finite population.
Open Hypergeometric Distribution Calculator →Idling Fuel Consumption Calculator
Work out fuel, cost and CO2 from idling an engine.
Open Idling Fuel Consumption Calculator →IELTS Score Calculator
Estimate IELTS bands from Listening and Reading raw scores plus practice Writing and Speaking bands.
Open IELTS Score Calculator →Impact Factor Calculator
Compute a journal 2-year and 5-year impact factor from citations and citable items.
Open Impact Factor Calculator →Index of Qualitative Variation Calculator
Measure categorical spread on a 0 to 1 scale with the index of qualitative variation.
Open Index of Qualitative Variation Calculator →Inequality Calculator
Solve a linear inequality and write the answer in interval notation.
Open Inequality Calculator →Ionic Strength Calculator
Compute ionic strength and the dilute-solution activity coefficient from ion concentrations.
Open Ionic Strength Calculator →Isoelectric Point Calculator
Find an amino acid’s isoelectric point (pI) from its pKa values and estimate its net charge at any pH.
Open Isoelectric Point Calculator →Keystrokes Per Hour Calculator
Convert keystrokes and typing time into keystrokes per hour, per minute, per second and an equivalent words-per-minute rate.
Open Keystrokes Per Hour Calculator →Lagrange Error Bound Calculator
Bound the error of a Taylor polynomial with the Lagrange remainder: M times |x − a|^(n+1) divided by (n+1)!.
Open Lagrange Error Bound Calculator →Langmuir Isotherm Calculator
Model monolayer adsorption with the Langmuir isotherm: adsorbed amount, surface coverage and the separation factor from qmax, KL and concentration.
Open Langmuir Isotherm Calculator →Lattice Energy Calculator
Estimate lattice energy with the Born–Landé model and the Kapustinskii equation — clearly labelled estimates, not measured enthalpies.
Open Lattice Energy Calculator →Lead Time Calculator
Add processing, transit and buffer days to an order date to get the total lead time and the expected delivery date.
Open Lead Time Calculator →Line Equation Calculator
Find the equation of a line through two points, with slope, intercept, midpoint and distance between the points.
Open Line Equation Calculator →Linear Feedback Shift Register Calculator
Simulate a Fibonacci LFSR: enter a binary seed and tap positions, and get the output sequence, state trace and maximum period.
Open Linear Feedback Shift Register Calculator →Linear Inches Calculator
Add length, width and height into total linear inches — the baggage-size measure airlines use — with a 62-inch limit check.
Open Linear Inches Calculator →Liquid Ethylene Density Calculator
Estimate saturated liquid ethylene density from temperature with the Rackett equation — a labelled estimate, not a NIST table value.
Open Liquid Ethylene Density Calculator →Logarithm Expression Calculator
Condense a sum and difference of logarithms into a single logarithm: a·log(x) + c·log(y) − d·log(z) becomes one log of a single argument.
Open Logarithm Expression Calculator →Lognormal Distribution Calculator
Evaluate a lognormal distribution: PDF, CDF, mean, median, mode and variance from μ, σ and x.
Open Lognormal Distribution Calculator →Long Arithmetic Calculator
Add, subtract and multiply whole numbers with a worked column-by-column trace, using exact big-integer arithmetic.
Open Long Arithmetic Calculator →Magic Number Calculator
Compute a sports team’s magic number — the combination of its wins and its rival’s losses needed to clinch.
Open Magic Number Calculator →Magic Square Generator
Generate a magic square where every row, column and diagonal sums to the same magic constant, for odd orders and multiples of 4.
Open Magic Square Generator →Manhattan Distance Calculator
Find the Manhattan (taxicab) distance between two points, with Euclidean and Chebyshev distances for comparison.
Open Manhattan Distance Calculator →Mann-Whitney U Test Calculator
Run a Mann-Whitney U test on two independent samples: U statistics, rank sums, a normal-approximation z and p-value.
Open Mann-Whitney U Test Calculator →Mass Concentration to Molar Concentration Converter
Convert mass concentration (g/L, mg/L or µg/L) to molar concentration (mol/L, mmol/L, µmol/L) using the molar mass.
Open Mass Concentration to Molar Concentration Converter →Matched Betting Calculator
Find the lay stake for a matched bet, with liability and profit for qualifying bets and free bets (stake not returned).
Open Matched Betting Calculator →Matrix Decomposition Calculator
Compute the LU decomposition (Doolittle, unit lower triangle) of a square matrix, with its determinant and a reconstruction check.
Open Matrix Decomposition Calculator →McNemar’s Test Calculator
Test paired nominal data with McNemar’s test: chi-square with and without continuity correction, plus approximate p-values.
Open McNemar’s Test Calculator →Mean Squared Error Calculator
Score predictions against actual values with mean squared error, root mean squared error, mean absolute error and bias.
Open Mean Squared Error Calculator →Median Absolute Deviation Calculator
Measure spread robustly with the median absolute deviation (MAD), its consistency-scaled form, the median and the mean.
Open Median Absolute Deviation Calculator →Michaelis-Menten Equation Calculator
Compute the reaction rate from the Michaelis-Menten equation, with the fraction of Vmax, Lineweaver-Burk reciprocals and the 90% substrate level.
Open Michaelis-Menten Equation Calculator →Miller Indices Calculator
Convert crystal-plane intercepts into Miller indices: take reciprocals, clear fractions and write the (hkl) form with bar notation.
Open Miller Indices Calculator →Mixing Ratio Calculator
Split any total by a mixing ratio, or simplify two amounts into their ratio, with each part and percentage.
Open Mixing Ratio Calculator →Modular Arithmetic Calculator
Compute a mod m and modular addition, subtraction, multiplication and powers, with the congruence shown.
Open Modular Arithmetic Calculator →Molality Calculator
Calculate molality from solute mass, molar mass and solvent mass, with moles and mass percent.
Open Molality Calculator →Molar Ratio Calculator
Simplify two mole amounts into a molar ratio, with per-mole and percentage shares.
Open Molar Ratio Calculator →Mole Fraction Calculator
Calculate mole fractions for a two- or three-component mixture from the mole amounts.
Open Mole Fraction Calculator →NaNoWriMo Calculator
Track a NaNoWriMo word goal: words remaining, daily pace needed, and whether you are ahead or behind.
Open NaNoWriMo Calculator →Negative Binomial Distribution Calculator
Calculate negative binomial probabilities: exactly k failures before the r-th success, plus the CDF, mean and variance.
Open Negative Binomial Distribution Calculator →Nernst Equation Calculator
Calculate a cell potential from the Nernst equation, with the RT/nF term and Gibbs free energy.
Open Nernst Equation Calculator →Neutralization Calculator
Find the base volume that neutralizes an acid, matching equivalents for polyprotic acids and bases.
Open Neutralization Calculator →Normal Distribution Calculator
Find normal probabilities, z-scores and density for any mean and standard deviation, including between-two-values.
Open Normal Distribution Calculator →Normality Calculator
Calculate normality from solute mass, molar mass, equivalents per mole and solution volume.
Open Normality Calculator →Nth Root Calculator
Find any nth root — square, cube or higher — with exact handling of negative radicands for odd n.
Open Nth Root Calculator →Odds Converter
Convert betting odds between decimal, fractional and American formats, with implied probability.
Open Odds Converter →Ordering Numbers Calculator
Order any list of numbers ascending or descending, with smallest, largest, median and count.
Open Ordering Numbers Calculator →Osmotic Pressure Calculator
Calculate osmotic pressure from molarity, temperature and the van’t Hoff factor, in atm and kPa.
Open Osmotic Pressure Calculator →Pallet Calculator
Work out boxes per layer, total boxes, stack height and total weight for a pallet load.
Open Pallet Calculator →Paper Weight Calculator
Calculate paper weight from sheet size, gsm and sheet count, with per-sheet and per-ream weights.
Open Paper Weight Calculator →Parabola Calculator
Analyse a parabola from vertex or standard form: vertex, focus, directrix, axis and roots.
Open Parabola Calculator →Parallelepiped Volume Calculator
Calculate parallelepiped volume from three edge vectors via the scalar triple product.
Open Parallelepiped Volume Calculator →Parallelogram Calculator
Calculate parallelogram area, perimeter, height and both diagonals from base, side and angle.
Open Parallelogram Calculator →Partial Fraction Decomposition Calculator
Decompose (ax + b) / ((x − r₁)(x − r₂)) into partial fractions, including repeated roots.
Open Partial Fraction Decomposition Calculator →Pascal’s Triangle Calculator
Generate Pascal’s triangle to any row, with the last row, its sum and binomial coefficients.
Open Pascal’s Triangle Calculator →Passer Rating Calculator
Calculate the official NFL passer rating from completions, attempts, yards, touchdowns and interceptions.
Open Passer Rating Calculator →Percent Composition Calculator
Find the percent composition of a mixture or compound from the mass of each part.
Open Percent Composition Calculator →Percent Ionic Character Calculator
Estimate the percent ionic character of a bond from the two atoms’ Pauling electronegativity values, with the bond type.
Open Percent Ionic Character Calculator →Percent Solution Calculator
Work out a solution’s percent concentration by mass, and how much solute a target percent needs.
Open Percent Solution Calculator →Percentage Concentration to Molarity Converter
Convert a percent concentration to molarity (mol/L) from the solute’s molar mass, with or without density.
Open Percentage Concentration to Molarity Converter →Percentile Calculator
Find the percentile rank of a score in a data set, with how many values fall below, equal to, and above it.
Open Percentile Calculator →Permutation and Combination Calculator
Compute both permutations nPr and combinations nCr for n items taken r at a time, with n! shown.
Open Permutation and Combination Calculator →Permutation Calculator
Compute permutations nPr for ordered selections of r items from n, plus the with-repetition count n^r.
Open Permutation Calculator →PERT Calculator
Estimate a project task’s expected time and standard deviation from optimistic, most likely and pessimistic estimates.
Open PERT Calculator →Phase Rule Calculator
Apply Gibbs’ phase rule to find a system’s degrees of freedom from its components and phases.
Open Phase Rule Calculator →Picture Frame Size Calculator
Work out the finished outer size of a framed picture from the print, mat and frame widths.
Open Picture Frame Size Calculator →Pie Chart Generator
Turn a list of values into pie-chart slices with percentages and angles, drawn on a canvas in the browser.
Open Pie Chart Generator →pKa Calculator
Find pKa from Ka, or from pH and the conjugate-base-to-acid ratio, with the acid strength.
Open pKa Calculator →Plane Equation Calculator
Find the Cartesian equation of a plane from a point on it and its normal vector.
Open Plane Equation Calculator →Pleated Skirt Calculator
Estimate fabric width, pleat spacing and total fabric for a pleated skirt from waist, length and pleat depth.
Open Pleated Skirt Calculator →Poker Odds Calculator
Work out exact Texas Hold’em drawing odds from your outs, for one or two cards to come.
Open Poker Odds Calculator →Polish Notation Converter
Convert between prefix, postfix and infix notation for arithmetic expressions.
Open Polish Notation Converter →Polynomial Calculator
Add, subtract or multiply two polynomials entered as coefficient lists.
Open Polynomial Calculator →Polynomial Factoring Calculator
Factor a quadratic trinomial ax² + bx + c over the integers or rationals where possible, with its roots.
Open Polynomial Factoring Calculator →Polynomial Regression Calculator
Fit a polynomial curve of degree 1–3 to paired data and read its equation, R² and error.
Open Polynomial Regression Calculator →Pool Salt Calculator
Work out how much salt to add to reach your pool’s target salinity from its volume and current level.
Open Pool Salt Calculator →Pool Shock Calculator
Work out how much shock chlorine to add to lift your pool’s free chlorine to the target level.
Open Pool Shock Calculator →Pool Table Room Size Calculator
Find the minimum room size for a pool table from the table size and cue length, with playing clearance.
Open Pool Table Room Size Calculator →Pooled Standard Deviation Calculator
Combine two samples’ standard deviations into one pooled standard deviation for a two-sample comparison.
Open Pooled Standard Deviation Calculator →Post-Test Probability Calculator
Turn a pre-test probability into post-test probabilities with a test’s sensitivity and specificity.
Open Post-Test Probability Calculator →Power Analysis Calculator
Estimate the sample size per group for a two-sample comparison from effect size, significance and power.
Open Power Analysis Calculator →PPM to Molarity Converter
Convert parts per million to molarity (mol/L) from the solute’s molar mass, with density for non-aqueous cases.
Open PPM to Molarity Converter →Prime Number Calculator
Test whether a number is prime and show its full prime factorisation, with trial division and deterministic Miller–Rabin checking.
Open Prime Number Calculator →Probability Paradox Simulator
Simulate the Monty Hall problem: compare staying with switching, with exact theory alongside a seeded simulation.
Open Probability Paradox Simulator →Process Capability Index Calculator
Calculate Cp, Cpu, Cpl and Cpk from specification limits, process mean and standard deviation, with expected defects per million.
Open Process Capability Index Calculator →Protein Solubility Calculator
Estimate relative protein solubility from pH, isoelectric point and ionic strength with a clearly stated estimator model.
Open Protein Solubility Calculator →PTE Score Calculator
Estimate PTE-style section and overall scores from practice-test percentages — a transparent guide only, never an official score.
Open PTE Score Calculator →Punch Force Calculator
Estimate average punch force, energy and pressure from effective mass, impact velocity, contact time and contact area.
Open Punch Force Calculator →Pyramid Calculator
Calculate the volume, surface area and slant heights of a rectangular pyramid from base length, width and height.
Open Pyramid Calculator →Pythagorean Triples Calculator
Generate all Pythagorean triples up to a maximum hypotenuse, with primitive triples counted separately.
Open Pythagorean Triples Calculator →Q10 Temperature Coefficient Calculator
Calculate the Q10 temperature coefficient from two rates measured at two temperatures.
Open Q10 Temperature Coefficient Calculator →Quadrilateral Calculator
Find the area and perimeter of any quadrilateral from its four sides and a diagonal, using the diagonal-split method.
Open Quadrilateral Calculator →Quaternion Calculator
Multiply quaternions, with norms, dot product, conjugate and inverse of the first quaternion.
Open Quaternion Calculator →Queueing Theory Calculator
Analyse an M/M/1 queue: utilisation, average queue length and waiting times from arrival and service rates.
Open Queueing Theory Calculator →Quilt Calculator
Plan a block quilt: block counts and fabric yardage estimates from quilt size, block size and fabric width.
Open Quilt Calculator →RAID Calculator
Calculate usable RAID capacity, efficiency and fault tolerance for RAID 0, 1, 5, 6 and 10.
Open RAID Calculator →Rainfall Volume Calculator
Convert rainfall over a roof or catchment area into harvestable water volume in litres, gallons and cubic metres.
Open Rainfall Volume Calculator →Raoult’s Law Calculator
Apply Raoult’s law to find a solution’s vapour pressure and vapour-pressure lowering from mole fractions.
Open Raoult’s Law Calculator →Rate Constant Calculator
Calculate a reaction rate constant and half-life from concentration change over time for zero, first and second order reactions.
Open Rate Constant Calculator →Rayleigh Distribution Calculator
Evaluate the Rayleigh distribution: density, cumulative probability, mean, median and mode for a given scale parameter.
Open Rayleigh Distribution Calculator →Reaction Quotient Calculator
Calculate the reaction quotient Q for aA + bB ⇌ cC + dD and compare it with K to predict the reaction direction.
Open Reaction Quotient Calculator →Reading Speed Calculator
Measure reading speed in words per minute from words read and time taken, with pages per hour and a speed class.
Open Reading Speed Calculator →Reading Time Calculator
Estimate how long a text will take to read from its word count and your reading speed.
Open Reading Time Calculator →Recessed Lighting Calculator
Plan a recessed lighting layout: spacing, rows, columns and total lights from room size and ceiling height.
Open Recessed Lighting Calculator →Reconstitution Calculator
Calculate reconstituted concentration and the volume to draw up for a prescribed dose from vial amount and diluent volume.
Open Reconstitution Calculator →Rectangle Calculator
Calculate a rectangle’s area, perimeter, diagonal and aspect ratio from its length and width.
Open Rectangle Calculator →Rectangular Prism (Cuboid) Calculator
Calculate a rectangular prism’s volume, surface area, space diagonal and edge length from length, width and height.
Open Rectangular Prism (Cuboid) Calculator →Regular Polygon Calculator
Find the area, perimeter, apothem and angles of any regular polygon from its side count and side length.
Open Regular Polygon Calculator →Relative Risk Calculator
Compare disease risk between exposed and unexposed groups with relative risk, risk difference, odds ratio and a 95% confidence interval.
Open Relative Risk Calculator →Relative Standard Error Calculator
Express a standard error as a percentage of its estimate to judge how precise a survey or sample estimate really is.
Open Relative Standard Error Calculator →Reorder Point Calculator
Find the stock level that should trigger a new order from daily demand, supplier lead time and safety stock.
Open Reorder Point Calculator →Resuspension Calculator
Work out the liquid volume needed to resuspend a pellet or powder at a target concentration, with aliquot counts.
Open Resuspension Calculator →Ring Size Calculator
Convert a finger measurement into US, UK and EU ring sizes, with the matching inner diameter.
Open Ring Size Calculator →Roll Length Calculator
Find how much material is wound on a roll from its outer diameter, core diameter and layer thickness.
Open Roll Length Calculator →Root Mean Square Calculator
Compute the root mean square of a set of numbers, the figure behind RMS voltage, audio levels and vibration analysis.
Open Root Mean Square Calculator →Roulette Payout Calculator
Work out roulette winnings, total return and win probability for every standard bet on European or American wheels.
Open Roulette Payout Calculator →Rounds Per Minute Calculator
Convert rounds fired and elapsed time into rounds per minute, rounds per second and time per round.
Open Rounds Per Minute Calculator →RPM Calculator
Convert revolutions and time into revolutions per minute, frequency, angular velocity and rotation period.
Open RPM Calculator →RSA Calculator
Generate RSA keys from two small primes and encrypt a test message to see the maths behind public-key cryptography.
Open RSA Calculator →Rug Size Calculator
Find the right rug size for a room from its dimensions and the bare-floor border you want to leave showing.
Open Rug Size Calculator →Sample Size Calculator
Find how many respondents a survey needs for a chosen confidence level, margin of error and population size.
Open Sample Size Calculator →Sampling Distribution Calculator
Find the standard error of a sample mean and the probability of observing a given sample mean from a population.
Open Sampling Distribution Calculator →Saponification Value Calculator
Calculate the saponification value of a fat or oil from a KOH titration: the milligrams of KOH needed per gram of oil.
Open Saponification Value Calculator →SAT Score Calculator
Estimate a digital SAT total from Reading and Writing and Math raw scores. A transparent practice estimator, not an official College Board score.
Open SAT Score Calculator →Scuba Weight Calculator
Estimate a starting scuba weight from body weight, exposure suit and water type, then fine-tune with a buoyancy check.
Open Scuba Weight Calculator →Shannon Entropy Calculator
Measure the information content of a distribution in bits, from probabilities or raw counts, with maximum and normalised entropy.
Open Shannon Entropy Calculator →Shoelace Length Calculator
Estimate the shoelace length a shoe needs from its eyelet count, eyelet spacing and the length left for tying.
Open Shoelace Length Calculator →Similar Triangles Calculator
Find the missing sides of a similar triangle from a scale factor, with perimeter and area ratios.
Open Similar Triangles Calculator →Simpson’s Diversity Index Calculator
Measure species diversity from abundance counts with Simpson’s diversity index, dominance and the reciprocal index.
Open Simpson’s Diversity Index Calculator →Skewness Calculator
Measure the asymmetry of a dataset with Fisher’s adjusted skewness, plus mean, median and standard deviation.
Open Skewness Calculator →Ski Size Calculator
Get a recommended ski length range from your height and ability level, with guidance for terrain and style.
Open Ski Size Calculator →Sock Loss Index Calculator
A light-hearted index for the great sock mystery: how many of your socks go missing, and how fast.
Open Sock Loss Index Calculator →Sock Size Calculator
Find your sock size from your foot length, with US, UK and EU equivalents and a letter size to shop by.
Open Sock Size Calculator →Sofa Size Calculator
Work out the right sofa length for your room, with walkway clearance, seat count and a depth guide.
Open Sofa Size Calculator →Speaking Time Calculator
Turn a word count into speaking time at slow, conversational or fast pace, with a realistic time range.
Open Speaking Time Calculator →Special Functions Calculator
Evaluate the gamma, log-gamma, beta and error functions with a documented Lanczos approximation.
Open Special Functions Calculator →Speedometer Gear Calculator
Find the driven speedometer gear teeth for your axle ratio and tyre size, with the speed error if you keep the old gear.
Open Speedometer Gear Calculator →Standard Error Calculator
Find the standard error of the mean from raw data or from a mean, standard deviation and sample size, with a 95% interval.
Open Standard Error Calculator →Stem and Leaf Plot Generator
Turn a list of numbers into a stem-and-leaf plot, drawn on canvas and as text, with count, range and median.
Open Stem and Leaf Plot Generator →Streaming Bitrate Calculator
Estimate the bitrate, hourly data use and upload speed a stream needs from resolution, frame rate and quality.
Open Streaming Bitrate Calculator →Sum of Digits Calculator
Add up the digits of any number, with its digital root, digit count and digit product.
Open Sum of Digits Calculator →Sum of Squares Calculator
Add the squares of a list of numbers, or of the first n natural numbers, with mean square and root mean square.
Open Sum of Squares Calculator →Tablecloth Size Calculator
Find the tablecloth size for a round or rectangular table, from the drop you want hanging over the edge.
Open Tablecloth Size Calculator →Takt Time Calculator
Find the takt time your line must hit from available production time and customer demand, and check it against cycle time.
Open Takt Time Calculator →TDS Calculator
Convert between electrical conductivity and total dissolved solids in water, with a plain-language water quality guide.
Open TDS Calculator →Tent Size Calculator
Find how much tent floor area your group needs and what manufacturer tent rating to buy for real comfort.
Open Tent Size Calculator →Tie Length Calculator
Find the tie length that lands at your belt buckle, adjusted for your height and your knot.
Open Tie Length Calculator →Toilet Paper Calculator
See how long a pack of toilet paper lasts your household, and what it costs per day.
Open Toilet Paper Calculator →Torus Calculator
Find the volume and surface area of a torus from its major and minor radii, with its ring, horn or spindle type.
Open Torus Calculator →Traffic Density Calculator
Turn a vehicle count and road length into traffic density per kilometre and per lane, with a level-of-service guide.
Open Traffic Density Calculator →Trapezoid Calculator
Find a trapezoid’s area, perimeter, median and diagonal from its two bases and height, with an isosceles option.
Open Trapezoid Calculator →Triangular Numbers Calculator
Find the nth triangular number, list the sequence, or test whether a number is triangular.
Open Triangular Numbers Calculator →Triangulation Calculator
Locate a target from a measured baseline and two sighting angles, using the law of sines.
Open Triangulation Calculator →Truth Table Calculator
Build a truth table for a logic expression with AND, OR, NOT, XOR, implication and equivalence, and classify it.
Open Truth Table Calculator →Turbo Size Calculator
Estimate the turbocharger airflow and pressure ratio your horsepower and boost target need, with a frame-size guide.
Open Turbo Size Calculator →TV Mounting Height Calculator
Find how high to mount your TV so the centre of the screen sits at seated eye level, with top, bottom and viewing distance.
Open TV Mounting Height Calculator →TV Size and Viewing Distance Calculator
Find the ideal viewing distance for any TV size, with THX and SMPTE recommendations from the screen width.
Open TV Size and Viewing Distance Calculator →Two-Photon Absorption Calculator
Calculate two-photon absorption transmission through a material from intensity, coefficient and path length.
Open Two-Photon Absorption Calculator →Uncertainty Calculator
Combine standard uncertainties by root-sum-of-squares and expand them to any coverage factor.
Open Uncertainty Calculator →Uniform Distribution Calculator
Compute the PDF, CDF, mean and variance of a continuous uniform distribution on any interval.
Open Uniform Distribution Calculator →Unit Circle Calculator
Find the unit-circle coordinates and sine, cosine and tangent for any angle.
Open Unit Circle Calculator →Uptime Calculator
Convert an uptime percentage into allowed downtime per day, week, month and year.
Open Uptime Calculator →Vapor Pressure Calculator
Estimate vapor pressure from temperature with the Antoine equation and published constants.
Open Vapor Pressure Calculator →Vapour Pressure of Water Calculator
Compute the saturation vapour pressure of water with the Buck equation, plus humidity quantities.
Open Vapour Pressure of Water Calculator →Variance Calculator
Compute population and sample variance and standard deviation from any list of numbers.
Open Variance Calculator →Vector Calculator
Add vectors, find magnitudes, dot and cross products, and the angle between two vectors.
Open Vector Calculator →Venn Diagram Generator
Draw a two-set Venn diagram from set sizes and read off the overlap, union and similarity.
Open Venn Diagram Generator →Vertical Exaggeration Calculator
Find the vertical exaggeration of a profile or cross-section from its horizontal and vertical scales.
Open Vertical Exaggeration Calculator →Video File Size Calculator
Estimate video file size from duration and video plus audio bitrate.
Open Video File Size Calculator →Water Hardness Calculator
Convert calcium and magnesium concentrations into total water hardness as CaCO₃, with a classification.
Open Water Hardness Calculator →Weibull Distribution Calculator
Compute Weibull PDF, CDF, reliability, mean and median from shape and scale parameters.
Open Weibull Distribution Calculator →What Grade Was I In Calculator
Work out which US school grade you were in for a given school year, from your birth date and the entry cutoff.
Open What Grade Was I In Calculator →Wheel Offset Calculator
Compare old and new wheels to see how offset and width change inner clearance and outer poke.
Open Wheel Offset Calculator →WHIP Calculator
Calculate a baseball pitcher’s WHIP from walks, hits allowed and innings pitched.
Open WHIP Calculator →White Christmas Calculator
Estimate the chance of a white Christmas from your own count of snowy Christmas Days, with a confidence interval.
Open White Christmas Calculator →Winch Size Calculator
Size a recovery winch from vehicle weight, slope and a safety factor, using the 1.5× rule.
Open Winch Size Calculator →Wind Chill Calculator
Calculate wind chill with the official NWS and Environment Canada formula, in Fahrenheit or Celsius.
Open Wind Chill Calculator →Windsock Calculator
Read a windsock: turn wind speed into sock angle and extension, and wind direction into sock pointing.
Open Windsock Calculator →Young-Laplace Equation Calculator
Calculate the Young-Laplace pressure difference across a curved liquid surface or soap bubble.
Open Young-Laplace Equation Calculator →Acres Per Hour Calculator
Calculate field work rate in acres per hour from implement width, speed and field efficiency.
Open Acres Per Hour Calculator →Animal Mortality Rate Calculator
Calculate animal mortality rate as a percentage and per 1,000 animals, with survival rate alongside.
Open Animal Mortality Rate Calculator →Basal Area Calculator
Calculate basal area per tree and per acre from diameter at breast height and trees per acre, for forestry and stand stocking work.
Open Basal Area Calculator →Bulb Spacing Calculator
Work out how many bulbs you need for a bed from its size and spacing, on both a square grid and a staggered (triangular) layout.
Open Bulb Spacing Calculator →Cattle Per Acre Calculator
Estimate how many cattle a pasture can carry from forage production, grazing days and animal weight — a stocking-rate estimate, not a guarantee.
Open Cattle Per Acre Calculator →CO2 Grow Room Calculator
Calculate how much CO2 to add to a grow room to lift it from its current level to a target concentration, in cubic feet, pounds and kilograms.
Open CO2 Grow Room Calculator →Compost Calculator
Balance a compost pile: find its carbon-to-nitrogen ratio from your greens and browns, and how much brown material brings it to 30:1.
Open Compost Calculator →Corn Yield Calculator
Estimate corn yield in bushels per acre from ear count, rows per ear and kernels per row, using the standard yield-component method.
Open Corn Yield Calculator →Daily Light Integral Calculator
Convert light intensity (PPFD) and photoperiod into daily light integral (DLI), and find the PPFD needed to hit a target DLI.
Open Daily Light Integral Calculator →Dry Matter Calculator
Find dry matter and moisture percentages from fresh and dry weights, and convert a fresh forage yield into dry matter yield.
Open Dry Matter Calculator →Feed Conversion Ratio Calculator
Calculate feed conversion ratio (FCR) from feed eaten and weight gained, plus feed efficiency, for livestock, poultry or aquaculture.
Open Feed Conversion Ratio Calculator →Fertilizer Calculator
Work out how much fertilizer product to apply from your target nitrogen rate, area and N-P-K grade, plus the phosphorus and potash it supplies.
Open Fertilizer Calculator →Grain Bin Calculator
Calculate grain bin volume in cubic feet and bushels from diameter, wall height and roof height, plus approximate wheat tonnage.
Open Grain Bin Calculator →Grain Conversion Calculator
Convert bushels to pounds, kilograms, metric tonnes and short tons using published standard bushel weights — weights vary by grain and region.
Open Grain Conversion Calculator →Grass Seed Calculator
Work out how much grass seed a lawn needs from its size and seeding rate, in pounds, kilograms and bags.
Open Grass Seed Calculator →Growing Degree Days Calculator
Calculate growing degree days (GDD) for a day from high and low temperatures, with the standard corn cap and base, plus a multi-day total.
Open Growing Degree Days Calculator →Livestock Fence Calculator
Work out fence posts, wire length and rolls for a rectangular paddock from its size, post spacing and number of wire strands.
Open Livestock Fence Calculator →Mowing Cost Calculator
Estimate mowing costs per visit, per month and per season from lawn area, price per acre and mowing frequency.
Open Mowing Cost Calculator →Mulch Calculator
Work out how much mulch a bed needs from its size and depth, in cubic feet, cubic yards, cubic metres and bags.
Open Mulch Calculator →Pine Straw Calculator
Work out how many bales of pine straw a bed needs from its size and bale coverage, plus the cost at your bale price.
Open Pine Straw Calculator →Plant Population Calculator
Calculate plants per acre from row spacing and in-row plant spacing, plus total plants for a field of any size.
Open Plant Population Calculator →Sod Calculator
Work out how much sod a lawn needs from its size and a waste allowance, in square feet, rolls and pallets.
Open Sod Calculator →Tree Age Calculator
Estimate a tree age from its trunk diameter and species growth factor — a rough guide, not an official or exact age.
Open Tree Age Calculator →Tree Diameter Calculator
Find a tree trunk diameter, radius and basal area from its circumference, measured with a tape around the trunk.
Open Tree Diameter Calculator →Tree Height Calculator
Estimate tree height from your distance to the tree and the angle to its top, using the clinometer (tangent) method.
Open Tree Height Calculator →Tree Leaf Count Calculator
Estimate how many leaves a tree carries from its crown size, leaf area index and average leaf size — a rough allometric estimate.
Open Tree Leaf Count Calculator →Tree Spacing Calculator
Calculate trees per acre from spacing on square and triangular layouts, plus total trees for a planting area.
Open Tree Spacing Calculator →Tree Value Calculator
Estimate the appraised value of a tree from trunk diameter, species, condition and location using a CTLA-style replacement-cost model.
Open Tree Value Calculator →Vapor Pressure Deficit Calculator
Calculate vapour pressure deficit (VPD) from air temperature and relative humidity, with an optional leaf-temperature VPD for greenhouse and grow-room control.
Open Vapor Pressure Deficit Calculator →Vegetable Seed Calculator
Work out how many vegetable seeds and packets you need from bed area, row and plant spacing, and germination rate.
Open Vegetable Seed Calculator →Vegetable Yield Calculator
Estimate total vegetable harvest from plant count and yield per plant, with yield per area and servings for kitchen-garden planning.
Open Vegetable Yield Calculator →Water Soluble Fertilizer Calculator
Calculate how much water-soluble fertilizer to dissolve for a target nitrogen concentration (ppm) and tank volume, with cost per batch.
Open Water Soluble Fertilizer Calculator →Air Changes Per Hour Calculator
Calculate air changes per hour (ACH) from room size and ventilation airflow, and find the airflow needed for a target ACH.
Open Air Changes Per Hour Calculator →Air Conditioner Size Calculator
Estimate air conditioner size in BTU per hour and tons from room area, sun exposure, occupants and kitchen heat, with a rule-of-thumb sizing guide.
Open Air Conditioner Size Calculator →Arch Calculator
Calculate circular arch geometry from span and rise: radius, arc length, central angle and segment area for masonry and carpentry layout.
Open Arch Calculator →Asphalt Calculator
Estimate asphalt volume and tonnage for driveways, paths and pads from length, width and depth, with waste allowance and material cost.
Open Asphalt Calculator →Baluster Calculator
Calculate how many balusters a railing needs and the even gap between them, keeping spacing within the 4-inch safety guideline.
Open Baluster Calculator →Beam Calculator
Calculate beam bending moment, reactions, section modulus and deflection for a simply supported beam under uniform load, for planning only.
Open Beam Calculator →Beam Span Calculator
Estimate the maximum span of a beam from its section, material and load using a deflection limit, for planning only.
Open Beam Span Calculator →Birdsmouth Cut Calculator
Calculate birdsmouth rafter cuts from roof pitch, rafter depth and wall-plate width: seat cut, plumb cut and remaining rafter depth.
Open Birdsmouth Cut Calculator →Boiler Size Calculator
Estimate boiler size in BTU per hour and kilowatts from heated area and climate, with pickup allowance and domestic hot water load.
Open Boiler Size Calculator →Bolt Circle Calculator
Calculate bolt circle geometry: hole spacing (chord), angular step, coordinates and circumference for flanges and wheel hubs.
Open Bolt Circle Calculator →Bolt Torque Calculator
Calculate bolt tightening torque from bolt diameter, clamp load and friction factor, in newton-metres, foot-pounds and inch-pounds.
Open Bolt Torque Calculator →Carbon Equivalent Calculator
Calculate carbon equivalent (CE) and Pcm from steel chemistry to judge weldability and preheat needs, using the IIW formula.
Open Carbon Equivalent Calculator →Carpet Calculator
Estimate carpet needed for a room by roll length or tile count, with waste allowance and material cost for flooring planning.
Open Carpet Calculator →Chicken Coop Size Calculator
Size a chicken coop and run from flock size: indoor area, outdoor run, nesting boxes, roost length and a suggested coop footprint.
Open Chicken Coop Size Calculator →Clearance Hole Calculator
Find the right clearance hole size for a bolt from ISO 273-based tables, with fine, medium and coarse fits and custom bolt sizes.
Open Clearance Hole Calculator →Concrete Driveway Cost Calculator
Estimate concrete driveway volume and material cost from length, width and slab depth, with waste allowance and extras.
Open Concrete Driveway Cost Calculator →Countersink Depth Calculator
Calculate countersink depth for flat-head screws from head diameter, pilot hole and countersink angle (82, 90, 100 or 120 degrees).
Open Countersink Depth Calculator →Deck Calculator
Estimate decking boards, joists and material cost for a rectangular deck from deck size, board width, gap and joist spacing.
Open Deck Calculator →DIY Shed Cost Calculator
Estimate DIY shed build cost from shed size, construction rate, roofing, foundation type, door and windows, with an itemised breakdown.
Open DIY Shed Cost Calculator →Door Header Size Calculator
Get a planning-guide door header size from opening width and wall type, with jack stud counts, for residential framing planning only.
Open Door Header Size Calculator →Electrical Box Fill Calculator
Check electrical box fill using NEC-style conductor volume allowances: enter conductors by gauge, devices and clamps, and compare with box volume.
Open Electrical Box Fill Calculator →Epoxy Calculator
Work out how much epoxy resin a project needs from surface area and pour thickness, including waste and the two-part mix split.
Open Epoxy Calculator →Fence Calculator
Estimate fence posts, panels, rails and pickets for a straight run or perimeter from length, post spacing and picket size.
Open Fence Calculator →Fence Cost Calculator
Estimate fence installation cost from length, cost per foot by material, and gates, with editable rates for local pricing.
Open Fence Cost Calculator →Fire Flow Calculator
Estimate the needed fire flow for a building using the ISO-style formula from construction type and effective area.
Open Fire Flow Calculator →Fire Glass Calculator
Work out how much fire glass a fire pit or fireplace needs from its shape, size and glass depth, in pounds and bags.
Open Fire Glass Calculator →Floor Area Ratio Calculator
Calculate floor area ratio (FAR) and site coverage from lot area and total building floor area, and check against a maximum FAR.
Open Floor Area Ratio Calculator →French Drain Calculator
Estimate gravel volume, pipe length and landscape fabric for a French drain from trench length, width and depth.
Open French Drain Calculator →Furnace Size Calculator
Estimate furnace heating output in BTU per hour from floor area, climate demand, ceiling height and insulation.
Open Furnace Size Calculator →Gambrel Roof Calculator
Work out gambrel roof geometry from span, lower-slope run and both pitches: rafter lengths, ridge height and roof area.
Open Gambrel Roof Calculator →Heat Loss Calculator
Estimate room heat loss in watts and BTU per hour from wall, window and roof areas, U-values, temperature difference and air changes.
Open Heat Loss Calculator →Hoop House Calculator
Size a hoop house or polytunnel from width, length, height and hoop spacing: hoop length, hoop count and plastic cover area.
Open Hoop House Calculator →Insulation Calculator
Work out how thick your insulation must be to reach a target R-value, plus the volume of material and the cost for the area you are insulating.
Open Insulation Calculator →K-Factor Calculator
Find the sheet-metal K-factor from a measured bend allowance, or work out the bend allowance and flat-pattern size from a known K-factor.
Open K-Factor Calculator →Lumber Weight Calculator
Estimate how much a board or a whole order weighs from its dimensions and species, with board feet included for ordering.
Open Lumber Weight Calculator →Material Removal Rate Calculator
Calculate machining material removal rate from width of cut, depth of cut and feed rate, for milling, turning and drilling estimates.
Open Material Removal Rate Calculator →Metal Punch Force Calculator
Estimate the tonnage needed to punch a hole in sheet metal from the hole shape, material thickness and shear strength.
Open Metal Punch Force Calculator →Metal Roof Cost Calculator
Estimate a metal roof budget from roof area, panel and labour rates, waste allowance, ridge and underlayment costs.
Open Metal Roof Cost Calculator →Metal Weight Calculator
Work out the weight of metal plate, bar and tube from its shape, dimensions and alloy, in pounds and kilograms.
Open Metal Weight Calculator →Miter Angle Calculator
Find the saw setting for picture-frame corners and angled joints — either from the number of sides in a polygon or from the angle two pieces meet at.
Open Miter Angle Calculator →Paint Calculator
Work out how many gallons of paint a room or a surface needs, for any number of coats, with waste and cost included.
Open Paint Calculator →Paver Calculator
Find how many pavers a patio, path or driveway needs from its area and the paver size, with cutting waste and cost included.
Open Paver Calculator →Pitch Diameter Calculator
Calculate thread pitch diameter for metric and imperial threads, or gear pitch diameter from tooth count and diametral pitch.
Open Pitch Diameter Calculator →Plywood Calculator
Work out how many plywood sheets cover a floor, wall or roof, with cutting waste and sheet cost included.
Open Plywood Calculator →Pond Calculator
Estimate a garden ponds volume in gallons, the liner size it needs, and its surface area from its shape and average depth.
Open Pond Calculator →Pool Volume Calculator
Calculate a swimming pools volume in gallons and litres from its shape and shallow and deep-end depths, plus fill time at your hose rate.
Open Pool Volume Calculator →Rafter Length Calculator
Find the common rafter length for a roof from its horizontal run and pitch, including the overhang tail beyond the wall.
Open Rafter Length Calculator →Retaining Wall Calculator
Estimate blocks, cap units and gravel for a retaining wall from its length, height and block size, with a waste allowance.
Open Retaining Wall Calculator →Rivet Size Calculator
Pick a standard rivet diameter and length from the sheet thickness and grip, using the classic workshop rules of thumb.
Open Rivet Size Calculator →Rolling Offset Calculator
Work out pipe rolling offsets: the true offset from horizontal and vertical offsets, and the travel length between fittings.
Open Rolling Offset Calculator →Roof Truss Calculator
Find the geometry of a simple symmetric roof truss — peak height, top-chord length and a rough lumber allowance — from span and pitch.
Open Roof Truss Calculator →Roofing Calculator
Estimate roofing material for a pitched roof: sloped area, squares and shingle bundles from footprint, pitch and waste.
Open Roofing Calculator →Round Pen Calculator
Work out how many panels a round pen needs from its diameter and panel length, plus the pen area in square feet and acres.
Open Round Pen Calculator →Sealant Calculator
Calculate how many sealant cartridges a joint needs from its length, width and depth, in cartridges and total volume.
Open Sealant Calculator →Siding Calculator
Estimate how many boxes of siding cover a wall area, after subtracting openings and adding cutting waste, with cost included.
Open Siding Calculator →Snow Load Calculator
Estimate the balanced roof snow load from ground snow load, roof pitch and exposure factors, using a simplified ASCE-style formula.
Open Snow Load Calculator →Spindle Speed Calculator
Spindle speed (RPM) from cutting speed and cutter diameter, in metric or imperial units, with feed rate from flutes and chip load.
Open Spindle Speed Calculator →Spiral Staircase Calculator
Spiral staircase layout from total rise: number of steps, actual riser height, angle per step and tread depth at the outer edge.
Open Spiral Staircase Calculator →Tank Volume Calculator
Tank volume for rectangular, vertical-cylinder, horizontal-cylinder and spherical tanks, in litres and gallons, including the filled volume at a given fill level.
Open Tank Volume Calculator →Taper Calculator
Taper ratio, taper per metre and included angle from large diameter, small diameter and taper length.
Open Taper Calculator →Thread Pitch Calculator
Convert between threads per inch (TPI) and thread pitch in millimetres, with approximate metric thread depth and tap drill size.
Open Thread Pitch Calculator →Tile Calculator
How many floor or wall tiles you need from room size, tile size and a waste allowance, with boxes and material cost.
Open Tile Calculator →True Position Calculator
True position (GD&T) deviation from nominal and measured hole coordinates, with a pass or fail check against the tolerance diameter.
Open True Position Calculator →Vertical Curve Calculator
Vertical curve design from entry and exit grades and curve length: grade change, K value, curve type and external distance.
Open Vertical Curve Calculator →Welding Calculator
Fillet weld metal volume and weight from leg size and weld length, with welding heat input from voltage, current and travel speed.
Open Welding Calculator →Battery Capacity Calculator
Battery energy capacity in watt-hours and milliamp-hours from voltage and amp-hours, with runtime at a given load.
Open Battery Capacity Calculator →Battery Life Calculator
How long a battery lasts from its capacity and the device’s current draw, with a derating for real-world efficiency.
Open Battery Life Calculator →Cable Impedance Calculator
Coaxial cable characteristic impedance from inner and outer conductor diameters and the dielectric constant, with velocity factor.
Open Cable Impedance Calculator →Duty Cycle Calculator
Duty cycle, off time and frequency from on time and period, with average voltage for a pulsed waveform.
Open Duty Cycle Calculator →Hamming Code Calculator
Encode 4 data bits as a Hamming(7,4) codeword with even or odd parity, showing each parity bit and the transmitted codeword.
Open Hamming Code Calculator →LM317 Calculator
LM317 adjustable regulator output voltage from R1 and R2, including the small adjustment-pin current term.
Open LM317 Calculator →Logic Gate Simulator
Interactive logic gate simulator: pick a gate, toggle inputs A and B, and see the output with the full truth table.
Open Logic Gate Simulator →Op-Amp Gain Calculator
Op-amp gain for inverting and non-inverting configurations from R1 and R2, with output voltage and gain in decibels.
Open Op-Amp Gain Calculator →Parity Bit Calculator
Even and odd parity bits for a binary string, with the transmitted word and the count of ones.
Open Parity Bit Calculator →PCB Trace Calculator
PCB trace width from current, temperature rise and copper weight using the IPC-2221 approximation, for external or internal layers.
Open PCB Trace Calculator →Pi Attenuator Calculator
Pi-network attenuator resistor values from attenuation in decibels and system impedance.
Open Pi Attenuator Calculator →RAM Latency Calculator
True RAM latency in nanoseconds from CAS latency and memory speed, with theoretical memory bandwidth.
Open RAM Latency Calculator →Speaker Box Calculator
Sealed speaker enclosure volume from driver Thiele-Small parameters, with system resonance for a chosen target Qtc.
Open Speaker Box Calculator →Total Harmonic Distortion Calculator
Total harmonic distortion from a list of harmonic amplitudes, in percent and decibels, from the fundamental onwards.
Open Total Harmonic Distortion Calculator →AI Water Footprint Calculator
ESTIMATE of the water footprint of AI use from daily queries and a water-per-query factor you can adjust — factors vary widely by model, data centre and source, so treat every figure as an estimate, never an exact measurement.
Open AI Water Footprint Calculator →Benzo[a]pyrene Calculator
ESTIMATE of daily benzo[a]pyrene (BaP) intake from air concentration, breathing rate and body weight — an exposure estimate for awareness, not a health assessment, and BaP levels vary greatly by place, season and source.
Open Benzo[a]pyrene Calculator →Books vs eBooks Calculator
Compare the estimated carbon footprint of printed books against eBooks, with adjustable per-book factors, so you can see when an e-reader pays back its footprint.
Open Books vs eBooks Calculator →Car vs Bike Calculator
Compare estimated car and cycling emissions for a regular commute, with distance, days per week and adjustable emission factors, plus the annual saving from switching.
Open Car vs Bike Calculator →Carrying Capacity Calculator
Estimate the carrying capacity of a habitat or system from its annual resource supply and per-person requirement, and see how current and projected populations compare with that limit.
Open Carrying Capacity Calculator →Cigarette Butts Calculator
Estimate how many cigarette butts a smoker or a group produces each year, how many are littered, and the weight of that litter, with an adjustable litter rate.
Open Cigarette Butts Calculator →CO2 Breathing Emission Calculator
Estimate the CO2 a person or group exhales from breathing rate and tidal volume, with daily and annual totals, using the physics of exhaled air.
Open CO2 Breathing Emission Calculator →Coffee Footprint Calculator
Estimate the carbon and water footprint of your coffee habit by cups per day and brew type, with adjustable water use per cup and clear estimate labelling.
Open Coffee Footprint Calculator →Cryptocurrency Footprint Calculator
Estimate the energy and CO2 footprint of cryptocurrency transactions by coin and volume, with an adjustable grid intensity, and see how wildly proof-of-work and proof-of-stake differ.
Open Cryptocurrency Footprint Calculator →Drip Faucet Calculator
Estimate how much water a dripping faucet wastes each day and year, and what it costs, from the drip rate and an adjustable drip size.
Open Drip Faucet Calculator →Eco Friendly Bags Calculator
Compare single-use plastic bags with a reusable bag: annual plastic use, annual footprint, and how many uses a reusable bag needs to break even.
Open Eco Friendly Bags Calculator →Fish Mercury Calculator
Estimate weekly mercury intake from fish by species, portion size and servings per week, compared with a reference weekly limit, with clear exposure assumptions.
Open Fish Mercury Calculator →Flight Emissions Calculator
Estimate flight CO2 and CO2e from distance, passengers and cabin class, with an adjustable per-passenger-kilometre factor and a radiative-forcing note.
Open Flight Emissions Calculator →Hand Dryers vs Paper Towels Calculator
Compare the estimated footprint of hand dryers against paper towels for a washroom, from daily uses and days open, with adjustable towel and dryer factors.
Open Hand Dryers vs Paper Towels Calculator →Hydroelectric Power Calculator
Calculate hydroelectric power from water flow rate and head height, with turbine efficiency, plus annual energy output and a household equivalent.
Open Hydroelectric Power Calculator →Kaya Identity Calculator
Break CO2 emissions into population, GDP per person, energy intensity and carbon intensity with the Kaya identity — all figures are estimates, as the factors vary by country and year.
Open Kaya Identity Calculator →Lotka-Volterra Equations Calculator
Find the equilibrium of a predator-prey system and simulate its cycles with the Lotka-Volterra equations.
Open Lotka-Volterra Equations Calculator →Meat Footprint Calculator
Estimate the annual carbon and water footprint of your meat eating from weekly amounts — ESTIMATES using stated average factors, which vary by farming system and region.
Open Meat Footprint Calculator →Passive House Calculator
Estimate a home’s space-heating demand and check it against the Passive House limit of 15 kWh per m2 per year — an estimate for planning, not a certification calculation.
Open Passive House Calculator →PHEV Economy Calculator
Work out what a plug-in hybrid really costs to run from its electric and petrol driving, with fuel and electricity prices you can edit.
Open PHEV Economy Calculator →Plastic Footprint Calculator
Estimate your annual plastic use and its carbon footprint from weekly single-use items — ESTIMATES using stated average item weights and a production factor that varies by plastic type.
Open Plastic Footprint Calculator →Reduce Your Plastic Calculator
Plan a plastic reduction: start from your current annual plastic use and model what percentage cuts save in kilograms, CO2e and items.
Open Reduce Your Plastic Calculator →Shannon Index Calculator
Measure species diversity from counts with the Shannon index, evenness and effective number of species — an ecological diversity index, distinct from information-theory entropy.
Open Shannon Index Calculator →Tree Benefits Calculator
Estimate what your trees give back each year — CO2 absorbed, oxygen, shade energy savings and stormwater intercepted — using stated per-tree estimates that vary by species, age and climate.
Open Tree Benefits Calculator →Vegan Footprint Calculator
Estimate the footprint of your current diet and what switching meals to plant-based would save — ESTIMATES using stated average factors for animal foods.
Open Vegan Footprint Calculator →Water Demand Calculator
Estimate average and peak water demand for a community or building from population and per-person use, with losses and a peak factor.
Open Water Demand Calculator →Wind Turbine Calculator
Calculate wind turbine power from rotor size, wind speed and efficiency, plus estimated annual energy — an estimate, since real output depends on the full wind distribution.
Open Wind Turbine Calculator →Wind Turbine Profit Calculator
Estimate whether a wind turbine pays: annual energy revenue against capital and operating costs, with simple payback and return — a planning estimate, not an investment appraisal.
Open Wind Turbine Profit Calculator →Zero Waste Christmas Tree Calculator
Compare a real, potted and artificial Christmas tree on footprint and waste — ESTIMATES using stated per-tree factors, since disposal route and reuse years change the answer most.
Open Zero Waste Christmas Tree Calculator →Air Fryer Calculator
Convert oven time and temperature to air fryer settings, with an energy-saving estimate — times and temperatures are guides; check food is cooked through.
Open Air Fryer Calculator →Alcohol by Volume Calculator
Calculate alcohol by volume (ABV) for homebrewing from original and final gravity, with an approximate calorie estimate.
Open Alcohol by Volume Calculator →Bacon Curing Calculator
Work out exact curing salt, sugar and curing time for homemade bacon — follow food-safety guidance: curing salt must be weighed accurately, never estimated by volume.
Open Bacon Curing Calculator →Baker’s Percentage Calculator
Scale any bread recipe with baker’s percentages: flour is always 100%, and every other ingredient is a percentage of flour weight.
Open Baker’s Percentage Calculator →BBQ Grill Size Calculator
Size a BBQ grill from your guest count: cooking area needed, suggested round diameter or rectangular size, and a size class.
Open BBQ Grill Size Calculator →BBQ Party Calculator
Plan a BBQ party: meat, buns, sides, drinks and charcoal from adult and child guest counts — quantities are guides; adjust for appetite and weather.
Open BBQ Party Calculator →Brine Calculator
Make a brine at the right strength: salt and sugar for your water volume, plus a brining time guide — keep brining food refrigerated throughout.
Open Brine Calculator →Butter Converter
Convert butter between grams, cups, tablespoons, sticks, ounces and pounds — using standard butter weights, which vary slightly by brand and temperature.
Open Butter Converter →Cake Pan Converter
Convert a cake recipe between pan sizes: batter scaling by pan area and an adjusted baking-time guide — check doneness, as ovens vary.
Open Cake Pan Converter →Cake Pricing Calculator
Price a cake to sell: ingredient and labour costs plus overhead and profit margin, with a per-serving price — a guide for home bakers, not tax or business advice.
Open Cake Pricing Calculator →Cake Serving Calculator
Work out how many servings a cake gives from its pan size and serving size — a guide; cutting style and appetite change the real count.
Open Cake Serving Calculator →Chilled Drink Calculator
Work out how much ice you need to chill a drink and how long chilling takes, by the fridge, freezer or an ice bath.
Open Chilled Drink Calculator →Coffee Brewing Calculator
Get the right coffee dose for any amount of water, with cups, strength and an estimated caffeine figure for your brew method.
Open Coffee Brewing Calculator →Coffee Kick Calculator
Estimate your caffeine kick from cups drunk, your body weight and the hours since drinking, with the caffeine still in your system.
Open Coffee Kick Calculator →Coffee to Water Ratio Calculator
Find your exact coffee-to-water ratio from the coffee and water you actually used, and see what water any target ratio would need.
Open Coffee to Water Ratio Calculator →Cold Brew Ratio Calculator
Plan cold brew from grounds and water to concentrate and ready-to-drink servings, with steep time and dilution guidance.
Open Cold Brew Ratio Calculator →Donut Calculator
Work out how many donuts and dozen boxes a party needs, with cost and a sensible buffer so nobody misses out.
Open Donut Calculator →Dry to Cooked Pasta Converter
Convert dry pasta to cooked weight and servings by shape, so you cook exactly enough and never a second potful by accident.
Open Dry to Cooked Pasta Converter →Egg Boiling Calculator
Get boiling times for soft, medium or hard eggs by egg size, starting temperature and altitude, with food-safety guidance.
Open Egg Boiling Calculator →Garlic Converter
Convert garlic between cloves, teaspoons and tablespoons of minced garlic, whole heads, grams and garlic powder.
Open Garlic Converter →Ham Cooking Calculator
Get ham cooking or reheating time by weight and type, with target internal temperature, resting time and serving estimates.
Open Ham Cooking Calculator →Ice Cream Calculator
Scale a classic ice-cream base to any batch size, with servings, cream, milk, sugar and egg yolks for your churn or no-churn method.
Open Ice Cream Calculator →Mashed Potatoes Calculator
Scale mashed potatoes for any table: raw potatoes, butter, milk and cream per serving, with mashing tips.
Open Mashed Potatoes Calculator →Molecular SO2 Calculator
Convert free SO2 and wine pH to active molecular SO2, and find the free SO2 needed for a protective 0.8 mg/L molecular level.
Open Molecular SO2 Calculator →Oil to Butter Converter
Convert between butter and oil in baking and cooking, in grams and tablespoons, with the standard 80% oil rule.
Open Oil to Butter Converter →Party Drink Calculator
Plan party drinks by guests and hours: total drinks, wine bottles, beer cans, soft drinks and ice, with a balanced drink mix.
Open Party Drink Calculator →Perfect Pancake Calculator
Scale pancake batter for any number of pancakes, with flour, milk, eggs, butter and pan guidance for fluffy results.
Open Perfect Pancake Calculator →Pizza Calculator
Plan a pizza by diameter and slices: area, dough, sauce and cheese weights, and area per slice.
Open Pizza Calculator →Pizza Comparison Calculator
Compare two pizzas by diameter and price to find the true best value per square inch, not just the cheaper box.
Open Pizza Comparison Calculator →Pizza Party Calculator
Work out how many pizzas a party needs from guests, slices per guest and slices per pizza, with cost and leftovers planning.
Open Pizza Party Calculator →Popcorn Calculator
Convert popcorn kernels to popped volume and servings, with oil and salt for stovetop popping.
Open Popcorn Calculator →Priming Sugar Calculator
Calculate priming sugar for homebrew carbonation by beer volume, target CO2 volumes and fermentation temperature.
Open Priming Sugar Calculator →Rice Water Ratio Calculator
Get water, cooked weight and servings for any rice type and amount, with absorption-method guidance.
Open Rice Water Ratio Calculator →Self Rising Flour Calculator
Make self-rising flour from plain flour with the right baking powder and salt, or work out the plain-flour equivalent.
Open Self Rising Flour Calculator →Sourdough Calculator
Scale sourdough by baker’s percentages: flour, water, starter and salt for any hydration and loaf size.
Open Sourdough Calculator →Steak Cook Time Calculator
Get steak cooking time by thickness and doneness, with target internal temperatures, resting time and thermometer guidance.
Open Steak Cook Time Calculator →Sulfur Calculator
Work out how much sulfur fertiliser or soil amendment you need for an area, from the elemental sulfur rate and the product strength.
Open Sulfur Calculator →Taco Bar Calculator
Plan a taco bar for any crowd: meat, tortillas, cheese, toppings and drinks from guest count and tacos per person.
Open Taco Bar Calculator →Tea Brewing Calculator
Brew tea properly: leaf weight, water, temperature and steep time for each tea type, plus an estimated caffeine total.
Open Tea Brewing Calculator →Thanksgiving Calculator
Plan the whole Thanksgiving dinner: turkey, sides, gravy, rolls and pies for your guest count and appetite level.
Open Thanksgiving Calculator →Turkey Cooking Time Calculator
Get a turkey cooking time range, rest time and oven start time from weight, stuffing and oven temperature.
Open Turkey Cooking Time Calculator →Turkey Defrost Calculator
Plan turkey thawing safely: fridge days or cold-water hours for any weight, with water-change counts.
Open Turkey Defrost Calculator →Turkey Size Calculator
Choose the right turkey size for your guests, appetite and leftovers goal, with a weight in lb and kg and an estimated cost.
Open Turkey Size Calculator →Uncooked to Cooked Rice Converter
Convert rice between uncooked and cooked amounts, by rice type, in cups or grams, with servings.
Open Uncooked to Cooked Rice Converter →Water Cooling Calculator
Model water cooling with Newton’s law of cooling: temperature after a time, or time to reach a target temperature.
Open Water Cooling Calculator →Wedding Alcohol Calculator
Estimate wedding drinks: total drinks, wine bottles, beer and spirit bottles from guests, hours and drink mix.
Open Wedding Alcohol Calculator →Yeast Converter
Convert yeast between instant, active dry and fresh yeast, in grams, with standard baker’s ratios.
Open Yeast Converter →D&D Encounter Calculator
Build a balanced D&D 5e encounter: monster XP, encounter multiplier and difficulty against your party’s XP budgets.
Open D&D Encounter Calculator →D&D Hit Points Calculator
Work out D&D 5e hit points by class hit die, level and Constitution modifier, using average rolls or maximum rolls.
Open D&D Hit Points Calculator →D&D Money Converter
Convert D&D 5e coins between copper, silver, electrum, gold and platinum, with a total in gold and a tidy breakdown.
Open D&D Money Converter →D&D Point Buy Calculator
Build D&D 5e ability scores with the 27-point point-buy system, with costs, remaining points and modifiers.
Open D&D Point Buy Calculator →Drop Chance Calculator
Work out drop odds: chance of at least one drop, expected drops, and attempts needed for 50%, 90% and 99% confidence.
Open Drop Chance Calculator →K/D Ratio Calculator
Calculate K/D ratio and KDA from kills, deaths and assists, with per-match averages for shooters and MOBAs.
Open K/D Ratio Calculator →Minecraft End Portal Finder
Plan a Minecraft End portal: prefilled-eye odds, eyes of ender still needed, and ender pearls and blaze rods to gather.
Open Minecraft End Portal Finder →Minecraft Stack Calculator
Convert Minecraft item counts into stacks, shulker boxes and chests for stack sizes of 64, 16 or 1.
Open Minecraft Stack Calculator →Pokemon Go Candy Calculator
Plan Pokemon GO evolutions: candy still needed, catches to go, and buddy walking distance for any evolution cost.
Open Pokemon Go Candy Calculator →Rust Decay Calculator
Estimate Rust base decay without upkeep: time left, HP lost per hour, and HP after a chosen time, by material and shelter.
Open Rust Decay Calculator →BPM Calculator
Convert BPM into beat, bar and note durations in seconds and milliseconds, for any time signature.
Open BPM Calculator →Chord Calculator
Build any chord from a root and quality: notes, intervals and frequencies in equal temperament (A4 = 440 Hz).
Open Chord Calculator →Chord Progression Generator
Generate chord progressions in any major or minor key from classic patterns, with each chord’s notes spelled out.
Open Chord Progression Generator →Delay and Reverb Time Calculator
Get tempo-synced delay and reverb times from BPM: dotted, triplet and straight note values in milliseconds.
Open Delay and Reverb Time Calculator →Fret Calculator
Find every fret position from your scale length, with fret spacing and the 12th-fret octave check.
Open Fret Calculator →Guitar String Tension Calculator
Work out a guitar string’s tension in pounds and kilograms from its gauge, scale length and pitch.
Open Guitar String Tension Calculator →Harmonic Series Calculator
Build the harmonic series above any fundamental, with each harmonic’s frequency, nearest note and tuning deviation.
Open Harmonic Series Calculator →Music Scale Calculator
Spell any scale from any root note, with its notes, intervals and frequencies.
Open Music Scale Calculator →Music Transposer
Transpose notes or a chord up or down by any number of semitones, in any key.
Open Music Transposer →Note Frequency Calculator
Get any note’s exact frequency, MIDI number and wavelength from its name and octave.
Open Note Frequency Calculator →Semitone Calculator
Measure the distance between two notes in semitones, with the interval name and frequency ratio.
Open Semitone Calculator →Vocal Range Calculator
Turn your lowest and highest singable notes into a range in semitones and a likely voice type.
Open Vocal Range Calculator →Bird Age Calculator
Convert your bird’s age into a human-age equivalent and life stage, by species lifespan.
Open Bird Age Calculator →Cat Adult Size Calculator
Predict your kitten’s adult weight from its current age and weight, by breed size.
Open Cat Adult Size Calculator →Cat Pregnancy Calculator
Find your cat’s due date from the mating date, with the usual delivery window and week-by-week milestones.
Open Cat Pregnancy Calculator →Cat Quality of Life Calculator
Score your cat’s quality of life on the HHHHHMM scale and see whether it is time to talk to your vet.
Open Cat Quality of Life Calculator →Cost of Owning a Dog Calculator
Budget the real cost of dog ownership: annual running costs and the lifetime total.
Open Cost of Owning a Dog Calculator →Cow Gestation Calculator
Find a cow’s expected calving date from the breeding date, with the usual calving window.
Open Cow Gestation Calculator →Dog Age Calculator
Convert your dog’s age into human years by size, with life stage and remaining life expectancy.
Open Dog Age Calculator →Dog Crate Size Calculator
Find the right crate size from your dog’s length and height, with standing and turning room included.
Open Dog Crate Size Calculator →Dog Food Calculator
Work out how many calories and cups of food your dog needs each day, by weight and life stage.
Open Dog Food Calculator →Dog Harness Size Calculator
Find your dog’s harness size from chest girth and neck, with a two-finger fit check.
Open Dog Harness Size Calculator →Dog Heat Cycle Calculator
Predict your dog’s next heat from her last one, with the usual window and fertile days.
Open Dog Heat Cycle Calculator →Dog Life Expectancy Calculator
Estimate your dog’s expected lifespan and remaining years from its size and current age.
Open Dog Life Expectancy Calculator →Dog Onion Toxicity Calculator
Work out how much onion your dog ate per kilogram of body weight — and what to do next.
Open Dog Onion Toxicity Calculator →Dog Quality of Life Calculator
Score your dog’s quality of life on the HHHHHMM scale and see whether it is time to talk to your vet.
Open Dog Quality of Life Calculator →Dog Raisin Toxicity Calculator
Work out how many raisins or grapes your dog ate per kilogram — and what to do next.
Open Dog Raisin Toxicity Calculator →Dog Size Calculator
Classify your dog’s size from its weight and height, with typical breed examples.
Open Dog Size Calculator →Dog Water Intake Calculator
Work out how much water your dog should drink each day, adjusted for activity and heat.
Open Dog Water Intake Calculator →Goat Gestation Calculator
Find a goat’s expected kidding window from the breeding date, using the normal 145–155 day gestation range.
Open Goat Gestation Calculator →Guinea Pig Age Calculator
Work out a guinea pig’s age in years, months and days from its birth date, with its life stage and share of a typical lifespan.
Open Guinea Pig Age Calculator →Guinea Pig Pregnancy Calculator
Estimate a guinea pig’s due window from the mating date, using the normal 59–72 day gestation range.
Open Guinea Pig Pregnancy Calculator →Hamster Age Calculator
Work out a hamster’s age in months and days from its birth date, with its life stage and share of a typical lifespan.
Open Hamster Age Calculator →Horse Gestation Calculator
Find a mare’s expected foaling window from the breeding date, using the normal 320–360 day gestation range.
Open Horse Gestation Calculator →Horse Weight Calculator
Estimate a horse’s weight from heart girth and body length using the standard weight-tape formula, in pounds and kilograms.
Open Horse Weight Calculator →Pet BMI Calculator
Calculate a rough body mass index for a dog or cat from weight and body length, as a screening guide alongside body condition scoring.
Open Pet BMI Calculator →Pet Calorie Calculator
Estimate a dog or cat’s daily calories from body weight using the standard resting energy requirement formula and life-stage multipliers.
Open Pet Calorie Calculator →Pet Chocolate Toxicity Calculator
Estimate theobromine dose per kilogram from chocolate type, amount eaten and dog weight, with toxicity bands and urgent veterinary guidance.
Open Pet Chocolate Toxicity Calculator →Pet Medication Dosage Calculator
Convert a veterinarian’s prescribed mg-per-kg dose and your pet’s weight into the total dose per administration and per day.
Open Pet Medication Dosage Calculator →Pet Sitter Rates Calculator
Estimate total pet-sitting cost from the daily rate, visits per day, number of days and extra-pet charges.
Open Pet Sitter Rates Calculator →Rabbit Cage Size Calculator
Check whether a rabbit enclosure meets commonly cited minimum space guidance, from its length, width and number of rabbits.
Open Rabbit Cage Size Calculator →Rabbit Gestation Calculator
Estimate a rabbit’s kindling window from the mating date, using the normal 28–35 day gestation range.
Open Rabbit Gestation Calculator →Rat Cage Size Calculator
Check whether a rat cage gives enough volume per rat, from its dimensions and the number of rats, against a 2.5 cubic feet per rat minimum.
Open Rat Cage Size Calculator →Raw Dog Food Calculator
Estimate daily raw food amounts for a dog from body weight and life stage, split into a commonly used BARF-style meat, bone, organ and vegetable mix.
Open Raw Dog Food Calculator →Sheep Gestation Calculator
Find a ewe’s expected lambing window from the tupping date, using the normal 142–152 day gestation range.
Open Sheep Gestation Calculator →Swine Gestation Calculator
Find a sow’s expected farrowing window from the breeding date, using the normal 110–118 day gestation range (the 3-3-3 rule).
Open Swine Gestation Calculator →Turtle Tank Size Calculator
Estimate minimum turtle tank size from shell length and turtle count, using the 10 gallons per inch of shell rule, in gallons and litres.
Open Turtle Tank Size Calculator →555 Timer Calculator
Calculate 555 timer astable frequency and duty cycle, or monostable pulse width, from resistor and capacitor values.
Open 555 Timer Calculator →Acceleration Due to Gravity Calculator
Calculate gravitational acceleration at any altitude above Earth from Newton’s law of gravitation, plus the weight of a given mass there.
Open Acceleration Due to Gravity Calculator →Acoustic Impedance Calculator
Calculate acoustic impedance from density and sound speed, and the reflection and transmission of sound at the boundary between two media.
Open Acoustic Impedance Calculator →Air Density Calculator
Calculate air density from pressure, temperature and humidity using the ideal gas law with a water-vapour correction.
Open Air Density Calculator →Alfven Velocity Calculator
Calculate the Alfvén wave speed in a plasma from magnetic field strength and ion number density, in metres and kilometres per second.
Open Alfven Velocity Calculator →Angle of Repose Calculator
Calculate the angle of repose of a granular pile from its height and base radius, with the slope ratio and gradient.
Open Angle of Repose Calculator →Angular Momentum Calculator
Calculate angular momentum and rotational kinetic energy from mass, size, angular velocity and shape, for point masses, spheres, discs and rods.
Open Angular Momentum Calculator →Angular Motion Calculator
Final angular velocity, angular displacement and revolutions for rotation at constant angular acceleration.
Open Angular Motion Calculator →Antenna Calculator
Half-wave dipole, quarter-wave and full-wave antenna lengths plus wavelength for any frequency.
Open Antenna Calculator →API Gravity Calculator
Convert specific gravity to API gravity degrees and classify the crude as light, medium, heavy or extra-heavy.
Open API Gravity Calculator →Attenuation Calculator
Total signal loss and output power over a cable or fibre run from the loss per kilometre and distance.
Open Attenuation Calculator →Ballistic Calculator
Bullet drop, remaining velocity, flight time and wind drift for a rifle shot, using SI ballistic-coefficient drag.
Open Ballistic Calculator →Bank Angle Calculator
Bank angle, load factor, turn rate and turn time for a level turn from speed and turn radius.
Open Bank Angle Calculator →Belt Length Calculator
Open-belt length, small-pulley wrap angle and belt speed from pulley diameters, centre distance and rpm.
Open Belt Length Calculator →Bend Allowance Calculator
Sheet-metal bend allowance, bend deduction, outside setback and flat-pattern length from angle, radius, thickness and K-factor.
Open Bend Allowance Calculator →Bernoulli Equation Calculator
Downstream pressure in a pipe or channel from upstream pressure, velocities, elevations and fluid density.
Open Bernoulli Equation Calculator →Black Hole Calculator
Schwarzschild radius, Hawking temperature, photon-sphere radius and ISCO for a non-rotating black hole.
Open Black Hole Calculator →Blackbody Radiation Calculator
Peak wavelength, total radiated power and spectral region for a blackbody at any temperature.
Open Blackbody Radiation Calculator →Blast Radius Calculator
Estimated overpressure radii and fireball size for a TNT-equivalent explosion, using cube-root scaling.
Open Blast Radius Calculator →Bohr Model Calculator
Orbital radius, energy level and electron velocity for a hydrogen-like atom, plus photon wavelength for a transition.
Open Bohr Model Calculator →Boltzmann Factor Calculator
Boltzmann factor, thermal energy kT and relative population of two energy levels from an energy gap and temperature.
Open Boltzmann Factor Calculator →Bragg’s Law Calculator
Bragg diffraction angle and 2θ from X-ray wavelength, crystal plane spacing and diffraction order.
Open Bragg’s Law Calculator →Buckling Calculator
Euler critical buckling load, critical stress, slenderness ratio and radius of gyration for a column.
Open Buckling Calculator →Buoyancy Calculator
Buoyant force, displaced mass and float-or-sink verdict for an object in fresh water, seawater, oil or mercury.
Open Buoyancy Calculator →Calorimetry Calculator
Heat absorbed or released from mass, specific heat and temperature change, with joules, kilojoules and calories.
Open Calorimetry Calculator →Capacitor Calculator
Charge, stored energy and capacitive reactance for a capacitor from capacitance, voltage and frequency.
Open Capacitor Calculator →Car Crash Force Calculator
Average impact force, deceleration in g, stopping distance and kinetic energy for a vehicle crash.
Open Car Crash Force Calculator →Centrifuge Calculator
Relative centrifugal force (×g), angular velocity and rotor tip speed from rpm and rotor radius.
Open Centrifuge Calculator →Charged Particle Acceleration Calculator
Acceleration, force and velocity gained by a charged particle in a uniform electric field.
Open Charged Particle Acceleration Calculator →Cloud Base Calculator
Estimated cloud-base height (lifting condensation level) from surface temperature and dew point.
Open Cloud Base Calculator →Compton Scattering Calculator
Compton wavelength shift, scattered wavelength and photon energy loss for X-ray or gamma scattering.
Open Compton Scattering Calculator →Conductivity to Resistivity Converter
Convert electrical conductivity to resistivity in ohm-metres, ohm-centimetres and kiloohm-metres.
Open Conductivity to Resistivity Converter →Coriolis Effect Calculator
Work out the Coriolis acceleration and force on a moving object from latitude, speed and mass, with the deflection direction for each hemisphere.
Open Coriolis Effect Calculator →Coulomb’s Law Calculator
Calculate the electrostatic force, potential energy and field between two point charges from their charges and separation.
Open Coulomb’s Law Calculator →Curie’s Law Calculator
Find the magnetic susceptibility and magnetisation of a paramagnetic material from its Curie constant, temperature and applied field.
Open Curie’s Law Calculator →Cyclotron Frequency Calculator
Calculate the cyclotron frequency, angular frequency, period and orbit radius of a charged particle in a uniform magnetic field.
Open Cyclotron Frequency Calculator →Cylinder Force Calculator
Work out the push and pull force of a hydraulic or pneumatic cylinder from bore diameter, rod diameter and working pressure.
Open Cylinder Force Calculator →Darcy’s Law Calculator
Calculate groundwater or porous-media flow from hydraulic conductivity, cross-sectional area, head difference and flow length.
Open Darcy’s Law Calculator →Darcy-Weisbach Calculator
Find pipe friction head loss and pressure drop from the friction factor, pipe length and diameter, flow velocity and fluid density.
Open Darcy-Weisbach Calculator →DC-DC Converter Calculator
Calculate buck and boost converter output voltage, output power and input current from input voltage, duty cycle and load current.
Open DC-DC Converter Calculator →De Broglie Wavelength Calculator
Find the de Broglie wavelength, momentum and kinetic energy of a particle from its type and speed, using the standard non-relativistic relation.
Open De Broglie Wavelength Calculator →Debye Length Calculator
Calculate the Debye screening length and electron plasma frequency of a plasma from electron density, temperature and relative permittivity.
Open Debye Length Calculator →Decibel Calculator
Convert between power ratios, amplitude ratios and decibels, and convert decibel values back to ratios, with plain-language interpretation.
Open Decibel Calculator →Delta to Wye Converter
Convert a delta resistor network to its equivalent wye (star) network, giving the three wye resistances that behave identically at the terminals.
Open Delta to Wye Converter →Diametral Pitch Calculator
Find a gear diametral pitch, module, circular pitch and addendum from tooth count and pitch diameter.
Open Diametral Pitch Calculator →Diffraction Calculator
Find the diffraction angle and screen position of a grating maximum from grating lines, diffraction order, wavelength and screen distance.
Open Diffraction Calculator →Diode Calculator
Calculate diode current, dynamic resistance and power from saturation current, forward voltage, ideality factor and temperature.
Open Diode Calculator →Diopter Calculator
Convert a lens focal length to diopters, or a diopter power to focal length, and tell whether the lens converges or diverges.
Open Diopter Calculator →Dipole Moment Calculator
Calculate an electric dipole moment in coulomb-metres and debyes from charge and charge separation.
Open Dipole Moment Calculator →Distance to Horizon Calculator
Find how far away the horizon is from any eye height, geometrically and with the standard atmospheric-refraction adjustment.
Open Distance to Horizon Calculator →Doppler Effect Calculator
Calculate the observed frequency of a sound when the source, the observer, or both are moving, for approaching and receding motion.
Open Doppler Effect Calculator →Drag Calculator
Calculate aerodynamic drag force and the power needed to overcome it from fluid density, speed, drag coefficient and frontal area.
Open Drag Calculator →Drake Equation Calculator
Explore the Drake equation for the number of detectable civilisations in the Milky Way — an illustrative model whose answer depends entirely on the speculative factors you enter.
Open Drake Equation Calculator →Drift Velocity Calculator
Calculate electron drift velocity and current density in a conductor from current, charge-carrier density and wire cross-section.
Open Drift Velocity Calculator →Elastic Moduli Calculator
Find stress, strain, Young’s modulus and shear modulus from load, cross-section, extension, original length and Poisson’s ratio.
Open Elastic Moduli Calculator →Electrical Mobility Calculator
Find charge-carrier mobility from drift velocity and electric field, and the resulting conductivity from carrier density.
Open Electrical Mobility Calculator →Electromagnetic Field Energy Density Calculator
Calculate the energy stored per cubic metre in an electric field, a magnetic field, or both combined, from field strengths.
Open Electromagnetic Field Energy Density Calculator →Engine Calculator
Calculate engine displacement from bore, stroke and cylinder count, in cubic centimetres, litres and cubic inches.
Open Engine Calculator →Enthalpy Calculator
Calculate enthalpy from internal energy, pressure and volume, or an enthalpy change from mass, specific heat and temperature change.
Open Enthalpy Calculator →Escape Velocity Calculator
Calculate escape velocity from a body’s mass and radius, with surface gravity, using the standard v = √(2GM/r) formula.
Open Escape Velocity Calculator →Factor of Safety Calculator
Calculate the factor of safety from a material’s failure or yield strength and the actual working stress, with a plain reading of the result.
Open Factor of Safety Calculator →Fermi Level Calculator
Calculate the Fermi energy, Fermi temperature and Fermi velocity of a free-electron gas from its electron density.
Open Fermi Level Calculator →Filter Calculator
Calculate the cutoff frequency of RC and RL low-pass filters from resistance and capacitance or inductance.
Open Filter Calculator →Flow Rate Calculator
Calculate volumetric flow rate from pipe diameter and flow velocity, in litres per second, cubic metres per hour and US gallons per minute.
Open Flow Rate Calculator →Flywheel Energy Storage Calculator
Calculate the kinetic energy stored in a spinning flywheel from its mass, radius and speed, in joules and kilowatt-hours.
Open Flywheel Energy Storage Calculator →Frequency Calculator
Convert between wave frequency, period and wavelength for a given wave speed, with angular frequency included.
Open Frequency Calculator →Froude Number Calculator
Calculate the Froude number from flow velocity and characteristic length, and read whether the flow is subcritical, critical or supercritical.
Open Froude Number Calculator →G-Force Calculator
Calculate g-force from centripetal motion (speed and turn radius) or from a linear speed change over time.
Open G-Force Calculator →Generator Power Calculator
Calculate generator real power, apparent power and current requirements for single-phase and three-phase loads.
Open Generator Power Calculator →Hall Coefficient Calculator
Calculate the Hall coefficient from carrier density, or from a measured Hall voltage, current, field and sample thickness.
Open Hall Coefficient Calculator →Heat Exchanger Calculator
Calculate heat duty and log mean temperature difference for a counter-flow heat exchanger from terminal temperatures, U-value and area.
Open Heat Exchanger Calculator →Heat Index Calculator
Calculate the heat index (feels-like temperature) from air temperature and relative humidity using the Rothfusz regression.
Open Heat Index Calculator →Heat Transfer Calculator
Calculate steady heat transfer by conduction through a wall or by convection from a surface, in watts.
Open Heat Transfer Calculator →Heisenberg Uncertainty Calculator
Calculate the minimum momentum uncertainty from a position uncertainty, and the corresponding velocity uncertainty for an electron or proton.
Open Heisenberg Uncertainty Calculator →Helmholtz Resonator Calculator
Calculate the resonant frequency of a Helmholtz resonator (bottle resonator) from neck size, neck length and cavity volume.
Open Helmholtz Resonator Calculator →Hoop Stress Calculator
Calculate hoop (circumferential) stress and longitudinal stress in a thin-walled pressure vessel from pressure, radius and wall thickness.
Open Hoop Stress Calculator →Hubble’s Law Calculator
Calculate a galaxy’s recession velocity from its distance using Hubble’s law, v = H₀·d, with the Hubble constant as an estimate.
Open Hubble’s Law Calculator →Hydrostatic Pressure Calculator
Calculate hydrostatic pressure at a depth from fluid density and depth, as gauge and absolute pressure.
Open Hydrostatic Pressure Calculator →Inclined Plane Calculator
Calculate the forces and acceleration on a block on an inclined plane from mass, slope angle and friction coefficient.
Open Inclined Plane Calculator →Inductor Calculator
Calculate inductance from coil turns, core area, length and permeability, plus inductive reactance at a chosen frequency.
Open Inductor Calculator →Intrinsic Carrier Concentration Calculator
Calculate the intrinsic carrier concentration ni of silicon, germanium or gallium arsenide from band gap and temperature.
Open Intrinsic Carrier Concentration Calculator →Inverse Square Law Calculator
Calculate intensity at a distance from a point source, and compare intensities at two distances, using the inverse square law.
Open Inverse Square Law Calculator →Isentropic Flow Calculator
Compute isentropic pressure, temperature and density ratios and the area–Mach relation for ideal-gas compressible flow.
Open Isentropic Flow Calculator →Knudsen Number Calculator
Find the Knudsen number from the mean free path and a characteristic length, and identify the flow regime.
Open Knudsen Number Calculator →Laser Beam Calculator
Calculate Rayleigh range, beam divergence and beam size at any distance for a Gaussian laser beam.
Open Laser Beam Calculator →Latent Heat Calculator
Work out the heat absorbed or released during melting, freezing, vaporisation or condensation.
Open Latent Heat Calculator →Length Contraction Calculator
Apply special relativity to find how a moving object’s length contracts and its Lorentz factor.
Open Length Contraction Calculator →Lens Equation Calculator
Solve the thin-lens equation for image distance, magnification and image type.
Open Lens Equation Calculator →Lever Calculator
Find the effort, mechanical advantage and efficiency of a simple lever.
Open Lever Calculator →Lift Coefficient Calculator
Compute the lift coefficient from lift, air density, airspeed and wing area.
Open Lift Coefficient Calculator →Lightning Distance Calculator
Estimate how far away lightning struck from the flash-to-thunder delay.
Open Lightning Distance Calculator →Lumens and Lux Calculator
Convert lumens to lux for a lit area or a point source, and find beam intensity.
Open Lumens and Lux Calculator →Luminosity Calculator
Estimate a star’s luminosity from its radius and surface temperature with the Stefan–Boltzmann law.
Open Luminosity Calculator →Mach Number Calculator
Compute Mach number from airspeed and altitude using the ISA speed of sound.
Open Mach Number Calculator →Magnetic Declination Calculator
Estimate magnetic declination from latitude and longitude with an approximate dipole model.
Open Magnetic Declination Calculator →Magnetic Field Calculator
Calculate the magnetic field of a straight wire, a solenoid or a circular loop.
Open Magnetic Field Calculator →Magnetic Force Calculator
Find the force on a current-carrying wire in a magnetic field.
Open Magnetic Force Calculator →Magnus Force Calculator
Estimate the Magnus lift on a spinning cylinder from spin, speed and size.
Open Magnus Force Calculator →Mass-Energy Calculator
Convert mass to energy with Einstein’s E = mc², in joules, kilowatt-hours and TNT equivalent.
Open Mass-Energy Calculator →Mean Free Path Calculator
Compute the mean free path, mean molecular speed and collision frequency of a gas.
Open Mean Free Path Calculator →MOSFET Calculator
Find a MOSFET’s drain current, operating region and power dissipation.
Open MOSFET Calculator →Newton’s Law of Cooling Calculator
Model exponential cooling or heating toward ambient temperature over time.
Open Newton’s Law of Cooling Calculator →NPSH Calculator
Calculate available net positive suction head and the margin against pump cavitation.
Open NPSH Calculator →Number Density Calculator
Find how many particles occupy a unit volume of an ideal gas or a material.
Open Number Density Calculator →Nusselt Number Calculator
Estimate the Nusselt number and convective heat-transfer coefficient for pipe flow.
Open Nusselt Number Calculator →Oblique Shock Calculator
Solve the oblique-shock θ–β–M relation for shock angle and downstream conditions.
Open Oblique Shock Calculator →Ohm’s Law Calculator
Solve Ohm’s law from any two of voltage, current, resistance and power.
Open Ohm’s Law Calculator →Open Channel Flow Calculator
Calculate open-channel discharge with the Manning equation for a rectangular channel, plus velocity and flow regime.
Open Open Channel Flow Calculator →Optical Density Calculator
Convert transmittance to optical density (absorbance) and see how much light is absorbed.
Open Optical Density Calculator →Orbital Mechanics Calculator
Find circular orbital velocity, period and escape velocity for Earth, the Moon, Mars or the Sun.
Open Orbital Mechanics Calculator →Orifice Flow Calculator
Estimate flow through a sharp-edged orifice from diameter, discharge coefficient and pressure drop.
Open Orifice Flow Calculator →Oscillation Calculator
Solve simple harmonic motion: angular frequency, period, peak velocity, acceleration and energy.
Open Oscillation Calculator →Parallax Calculator
Convert a stellar parallax angle into distance in parsecs and light-years.
Open Parallax Calculator →Pendulum Calculator
Find a simple pendulum’s period, frequency and maximum speed for small swings.
Open Pendulum Calculator →Photoelectric Effect Calculator
Apply Einstein’s photoelectric equation to find photon energy, kinetic energy and threshold wavelength.
Open Photoelectric Effect Calculator →Photon Energy Calculator
Convert photon wavelength to energy, frequency and momentum.
Open Photon Energy Calculator →Poiseuille’s Law Calculator
Calculate laminar volume flow through a circular tube from pressure drop, radius, viscosity and length.
Open Poiseuille’s Law Calculator →Polarization Calculator
Apply Malus’s law for transmitted intensity and find the Brewster angle for two media.
Open Polarization Calculator →Power to Weight Ratio Calculator
Compare power and mass as watts per kilogram and horsepower per tonne.
Open Power to Weight Ratio Calculator →Prandtl Number Calculator
Compute the Prandtl number from viscosity, specific heat and thermal conductivity.
Open Prandtl Number Calculator →Prandtl-Meyer Expansion Calculator
Evaluate the Prandtl-Meyer function, Mach angle and downstream Mach number for an ideal-gas expansion.
Open Prandtl-Meyer Expansion Calculator →Pressure Calculator
Compute pressure from force and area, with conversions to kilopascals, bar, psi, atmospheres and millimetres of mercury.
Open Pressure Calculator →Principal Stress Calculator
Find principal stresses, maximum shear stress and principal angle for plane stress.
Open Principal Stress Calculator →Propeller Calculator
Estimate static thrust, induced velocity and tip speed from shaft power and diameter using simplified momentum theory.
Open Propeller Calculator →Psychrometric Calculator
Estimate dew point, humidity ratio, enthalpy and absolute humidity from temperature and relative humidity.
Open Psychrometric Calculator →Pulley Calculator
Find the effort force, mechanical advantage and rope pulled for a pulley system.
Open Pulley Calculator →Pump Horsepower Calculator
Convert pump flow and head into hydraulic and shaft horsepower, with efficiency included.
Open Pump Horsepower Calculator →Radiation Pressure Calculator
Find the pressure and force exerted by light on absorbing or reflecting surfaces.
Open Radiation Pressure Calculator →Reactance Calculator
Compute inductive and capacitive reactance, series impedance, phase angle and resonant frequency.
Open Reactance Calculator →Reduced Mass Calculator
Compute the reduced mass of a two-body system from the two masses.
Open Reduced Mass Calculator →Relativistic Kinetic Energy Calculator
Find relativistic kinetic energy, the Lorentz factor and momentum at a fraction of light speed.
Open Relativistic Kinetic Energy Calculator →Resistor Noise Calculator
Estimate Johnson-Nyquist thermal noise voltage for a resistor over a given bandwidth.
Open Resistor Noise Calculator →Reverberation Time Calculator
Estimate a room’s reverberation time (RT60) with the Sabine formula from its volume and total sound absorption.
Open Reverberation Time Calculator →RF Link Budget Calculator
Work out free-space path loss, received power and link margin for a wireless link from frequency, distance and antenna gains.
Open RF Link Budget Calculator →RLC Circuit Calculator
Find the resonant frequency, Q factor and bandwidth of a series RLC circuit from resistance, inductance and capacitance.
Open RLC Circuit Calculator →RMS Velocity Calculator
Calculate the root-mean-square, mean and most probable speeds of gas molecules from temperature and molar mass.
Open RMS Velocity Calculator →Rocket Calculator
Apply the Tsiolkovsky rocket equation to find delta-v, mass ratio and propellant mass from specific impulse and vehicle masses.
Open Rocket Calculator →Rolling Resistance Calculator
Estimate rolling resistance force, power loss and energy per kilometre for a vehicle from its mass, tyre coefficient and speed.
Open Rolling Resistance Calculator →Rotational Kinetic Energy Calculator
Calculate rotational kinetic energy, angular velocity and angular momentum from moment of inertia and rotation speed.
Open Rotational Kinetic Energy Calculator →Rydberg Equation Calculator
Use the Rydberg formula to find the wavelength, frequency and photon energy of a hydrogen spectral line from its electron levels.
Open Rydberg Equation Calculator →Section Modulus Calculator
Calculate section modulus, second moment of area and radius of gyration for rectangular and circular beam sections.
Open Section Modulus Calculator →Series Resistor Calculator
Add resistors in series and find total resistance, circuit current, power dissipation and the voltage across the first resistor.
Open Series Resistor Calculator →Shear Wave Velocity Calculator
Find seismic shear-wave (S-wave) velocity from shear modulus and density, plus travel time over a chosen distance.
Open Shear Wave Velocity Calculator →Signal to Noise Ratio Calculator
Convert signal and noise levels into signal-to-noise ratio in decibels and as a linear ratio, for power or voltage quantities.
Open Signal to Noise Ratio Calculator →Skin Depth Calculator
Calculate the electromagnetic skin depth in a conductor from its resistivity, the frequency and its relative permeability.
Open Skin Depth Calculator →Snell’s Law Calculator
Find the refraction angle from Snell’s law, plus the critical angle for total internal reflection when light leaves a denser medium.
Open Snell’s Law Calculator →Sound Absorption Calculator
Find the average sound absorption coefficient of a room from its total absorption and total surface area.
Open Sound Absorption Calculator →Space Travel Calculator
Estimate interstellar travel times with special relativity: Earth-frame time, ship time, Lorentz factor and length contraction.
Open Space Travel Calculator →Speed of Light Calculator
Find the speed of light in a medium from its refractive index, and the time light takes to cross a chosen distance.
Open Speed of Light Calculator →Speed of Sound Calculator
Calculate the speed of sound in dry air from temperature, plus travel time over a chosen distance.
Open Speed of Sound Calculator →Speeds and Feeds Calculator
Calculate CNC spindle speed and feed rate from cutting speed, tool diameter, tooth count and feed per tooth.
Open Speeds and Feeds Calculator →Spring Calculator
Apply Hooke’s law to find spring force and stored elastic potential energy from spring constant and deflection.
Open Spring Calculator →Stokes’ Law Calculator
Calculate Stokes drag on a sphere and its terminal settling velocity from radius, viscosity, speed and densities.
Open Stokes’ Law Calculator →Stopping Distance Calculator
Find thinking distance, braking distance and total stopping distance for a vehicle from speed, reaction time and road friction.
Open Stopping Distance Calculator →Strain Calculator
Calculate engineering strain, microstrain and percentage elongation from a change in length and the original length.
Open Strain Calculator →Stress Calculator
Calculate normal stress in megapascals and psi from applied force and cross-sectional area, with utilisation against a yield strength.
Open Stress Calculator →Sunrise and Sunset Calculator
Estimate sunrise, sunset, solar noon and day length for any date and location with the standard NOAA solar-position algorithm.
Open Sunrise and Sunset Calculator →Surface Tension Calculator
Find surface tension from capillary rise, plus capillary length and common unit conversions.
Open Surface Tension Calculator →Telescope Calculator
Work out telescope magnification, focal ratio, resolution limits, exit pupil and limiting magnitude from aperture and eyepiece.
Open Telescope Calculator →Terminal Velocity Calculator
Estimate terminal velocity from mass, drag coefficient, frontal area and air density, with drag force and kinetic energy at that speed.
Open Terminal Velocity Calculator →Thermal Efficiency Calculator
Calculate thermal efficiency from useful work and heat input, with waste heat and the Carnot limit for the same temperatures.
Open Thermal Efficiency Calculator →Thermal Expansion Calculator
Find how much a material lengthens with temperature, plus approximate area and volume change, from its expansion coefficient.
Open Thermal Expansion Calculator →Thermal Properties Calculator
Derive thermal conductivity from measured heat flow through a slab, with heat flux and thermal resistance for the same setup.
Open Thermal Properties Calculator →Thin Film Optics Calculator
Find the film thickness for constructive interference at a chosen wavelength, with the next order and optical thickness.
Open Thin Film Optics Calculator →Three Phase Power Calculator
Calculate three-phase real, reactive and apparent power from line voltage, current and power factor.
Open Three Phase Power Calculator →TNT Equivalent Calculator
Convert an energy amount to its TNT equivalent in tonnes and kilograms, and to joules, megajoules and kilowatt-hours.
Open TNT Equivalent Calculator →Torsion Calculator
Calculate maximum shear stress and angle of twist for a solid circular shaft under torque, from diameter, length and shear modulus.
Open Torsion Calculator →Transformer Calculator
Find secondary voltage and current from turns ratio and primary values, with input power and output power at a stated efficiency.
Open Transformer Calculator →Transistor Biasing Calculator
Analyse a voltage-divider-biased NPN transistor stage: base voltage, collector current and collector-emitter voltage.
Open Transistor Biasing Calculator →True Airspeed Calculator
Convert indicated airspeed to true airspeed using altitude and outside air temperature, with Mach number as an extra check.
Open True Airspeed Calculator →Valve Flow Coefficient Calculator
Find the valve flow coefficient Cv (and metric Kv) from flow rate, specific gravity and pressure drop across the valve.
Open Valve Flow Coefficient Calculator →Van der Waals Equation Calculator
Solve the Van der Waals equation for a real gas pressure, and compare it with the ideal-gas pressure and compressibility factor.
Open Van der Waals Equation Calculator →Velocity Addition Calculator
Add two velocities relativistically and compare with the classical sum, in fractions of light speed and in km/s.
Open Velocity Addition Calculator →Viscosity Calculator
Convert kinematic viscosity and density to dynamic viscosity, with shear stress at a stated shear rate.
Open Viscosity Calculator →Voltage and Current Divider Calculator
Calculate voltage-divider output or current-divider branch currents from two resistors and the source value.
Open Voltage and Current Divider Calculator →VSWR Calculator
Convert reflection coefficient or forward/reflected power to VSWR, return loss and mismatch loss.
Open VSWR Calculator →Water Heating Calculator
Find the energy and time needed to heat a volume of water, plus cost at a stated electricity price.
Open Water Heating Calculator →Wave Speed Calculator
Find wave speed from frequency and wavelength, with period, angular frequency and wavenumber.
Open Wave Speed Calculator →Weight on Other Planets Calculator
Find how much you would weigh on every planet and the Moon, from your mass, with Earth weight for comparison.
Open Weight on Other Planets Calculator →Wheatstone Bridge Calculator
Find Wheatstone bridge output voltage and the unknown resistance for balance, from the four arm resistances and supply voltage.
Open Wheatstone Bridge Calculator →Wind Load Calculator
Estimate wind pressure and total wind force on a surface from wind speed, area and pressure coefficient.
Open Wind Load Calculator →Wing Loading Calculator
Calculate wing loading from aircraft weight and wing area, with an estimated stall speed at a stated maximum lift coefficient.
Open Wing Loading Calculator →Wire Resistance Calculator
Calculate the resistance of a wire from its material, length and cross-sectional area, plus voltage drop and power loss.
Open Wire Resistance Calculator →Wire Size Calculator
Size a wire for a load: find the minimum cross-section and nearest standard gauge for a target voltage drop.
Open Wire Size Calculator →Y+ Calculator
Compute the dimensionless wall distance y+ from wall shear stress, fluid properties and distance from the wall.
Open Y+ Calculator →Allele Frequency Calculator
Find allele frequencies p and q from observed genotype counts, plus observed heterozygosity.
Open Allele Frequency Calculator →Annealing Temperature Calculator
Estimate a primer’s melting temperature and a starting annealing temperature from its sequence.
Open Annealing Temperature Calculator →Bacteria Growth Calculator
Project bacterial population growth from the starting count, doubling time and elapsed time under ideal exponential growth.
Open Bacteria Growth Calculator →Cell Doubling Time Calculator
Find a cell population’s doubling time from starting and final counts over a known interval.
Open Cell Doubling Time Calculator →Cricket Chirp Thermometer
Estimate air temperature from cricket chirps using Dolbear’s law — a classic field estimate, not a thermometer.
Open Cricket Chirp Thermometer →Dihybrid Cross Calculator
Work out offspring phenotype ratios for a two-trait Mendelian cross with a full 16-cell Punnett square.
Open Dihybrid Cross Calculator →DNA Concentration Calculator
Convert an A260 reading into DNA concentration and total yield, with an A260/A280 purity check.
Open DNA Concentration Calculator →DNA Copy Number Calculator
Convert DNA concentration and fragment length into copies per microlitre and total copies.
Open DNA Copy Number Calculator →DNA to mRNA Converter
Transcribe a DNA sequence into mRNA — from the coding strand or the template strand — with length and GC content.
Open DNA to mRNA Converter →Hardy-Weinberg Equilibrium Calculator
Compute expected genotype frequencies and counts under Hardy–Weinberg equilibrium from an allele frequency.
Open Hardy-Weinberg Equilibrium Calculator →Ligation Calculator
Calculate how much insert DNA to use in a ligation from vector amount, fragment sizes and molar ratio.
Open Ligation Calculator →Log Reduction Calculator
Convert before-and-after microbial counts into log reduction value, percentage reduction and fold reduction.
Open Log Reduction Calculator →MLVSS Calculator
Compute mixed liquor volatile suspended solids (MLVSS) from MLSS and the volatile fraction, plus basin inventory.
Open MLVSS Calculator →Mutation Frequency Calculator
Find mutation frequency from mutant colonies and total viable cells plated.
Open Mutation Frequency Calculator →Mutation Rate Calculator
Estimate mutation rate per base pair per generation from observed mutations, generations, genome size and lineages.
Open Mutation Rate Calculator →Protein Concentration Calculator
Find protein concentration from A280 using an extinction coefficient — entered directly or built from amino-acid counts.
Open Protein Concentration Calculator →Protein Molecular Weight Calculator
Calculate a protein’s molecular weight from its amino-acid sequence using average residue masses.
Open Protein Molecular Weight Calculator →Punnett Square Calculator
Build a Punnett square from two parents’ genotypes and read off offspring genotype and phenotype probabilities.
Open Punnett Square Calculator →qPCR Efficiency Calculator
Turn a qPCR standard-curve slope into amplification efficiency and judge whether the assay is in the acceptable range.
Open qPCR Efficiency Calculator →Rabbit Coat Color Calculator
Predict rabbit coat-colour outcomes from the parents’ simplified five-locus genotypes, with per-locus probabilities.
Open Rabbit Coat Color Calculator →Trihybrid Cross Calculator
Work out trihybrid cross outcomes for three independent genes, with all eight phenotype classes and dominant-trait counts.
Open Trihybrid Cross Calculator →Water Potential Calculator
Calculate plant water potential from solute and pressure potentials, with unit conversion and the direction water will move.
Open Water Potential Calculator →ASCII Converter
Convert text to ASCII codes and back, in decimal, hexadecimal or binary, with invalid characters clearly rejected.
Open ASCII Converter →Binary to Text Converter
Convert text to binary and binary back to text using UTF-8, with strict validation of every bit group.
Open Binary to Text Converter →Floating Point Converter
See exactly how a decimal becomes IEEE 754 float32 or float64 bits, and what value is actually stored.
Open Floating Point Converter →Hash Identifier
Identify a hash’s possible algorithms from its length and pattern, with an honest warning about what length alone cannot prove.
Open Hash Identifier →Hex to Text Converter
Convert text to hexadecimal and hex back to text using UTF-8, rejecting odd-length or non-hex input.
Open Hex to Text Converter →IP Address Converter
Convert IPv4 addresses between dotted-decimal, integer, hex and binary, with class and private/public identification.
Open IP Address Converter →Leet Speak Translator
Translate text into leet speak (1337) at three strengths, and decode leet back to plain text as far as it can be reversed.
Open Leet Speak Translator →Letters to Numbers Converter
Convert letters to numbers with the A1Z26 cipher (a=1 to z=26) and decode numbers back to letters.
Open Letters to Numbers Converter →Morse Code Translator
Translate text to Morse code and Morse code back to text, using standard ITU codes with clear errors for invalid sequences.
Open Morse Code Translator →NATO Phonetic Alphabet Converter
Convert text to the NATO phonetic alphabet (Alfa, Bravo, Charlie…) and phonetic words back to letters and digits.
Open NATO Phonetic Alphabet Converter →Numbers to Words Converter
Convert numbers to English words and English number words back to digits, including decimals and negative numbers.
Open Numbers to Words Converter →Pig Latin Translator
Translate English to Pig Latin and Pig Latin back to English, handling vowels, consonant clusters, qu and capitalisation.
Open Pig Latin Translator →T9 to Text Converter
Convert text to T9 phone-keypad digits and T9 digits to every possible letter combination, with the ambiguity shown plainly.
Open T9 to Text Converter →Unicode Text Converter
Convert text to Unicode code points with UTF-8, UTF-16 and HTML entities, and code points back to text.
Open Unicode Text Converter →Wingdings Translator
Translate text into Wingdings-style symbols and symbols back to letters, with the font-approximation limits stated plainly.
Open Wingdings Translator →Camera Field of View Calculator
Find a lens and sensor combination’s horizontal, vertical and diagonal field of view, plus the scene width it covers at a given distance.
Open Camera Field of View Calculator →Depth of Field Calculator
Work out near and far depth-of-field limits, total depth of field and hyperfocal distance from focal length, aperture, subject distance and sensor.
Open Depth of Field Calculator →Exposure Calculator
Find the exposure value of an aperture, shutter speed and ISO combination, plus equivalent settings that give the same exposure.
Open Exposure Calculator →Focal Length Calculator
Convert between actual and 35 mm-equivalent focal length with crop-factor presets, and see the angle of view of the result.
Open Focal Length Calculator →Ground Sample Distance Calculator
Work out drone and aerial survey ground sample distance in cm per pixel, plus the ground footprint of each image.
Open Ground Sample Distance Calculator →Image File Size Calculator
Find the uncompressed size of an image from its pixel dimensions, bit depth and channels, plus rough JPEG and PNG estimates.
Open Image File Size Calculator →Pixels Per Inch Calculator
Find a display or image PPI from pixel dimensions and diagonal size, plus megapixels and the print size at a chosen DPI.
Open Pixels Per Inch Calculator →Pixels to Print Size Calculator
Convert pixel dimensions to physical print size in inches and centimetres at any DPI, with a quality verdict for the DPI band.
Open Pixels to Print Size Calculator →Projector Calculator
Work out projector image width from throw distance and throw ratio, or the distance you need for a target screen width.
Open Projector Calculator →Resolution Scale Calculator
Scale any resolution by percentage or to a target width, and compare two resolutions, with megapixel change.
Open Resolution Scale Calculator →Screen Size Calculator
Find a screen’s width and height from its diagonal and aspect ratio, or its diagonal from width and height.
Open Screen Size Calculator →Time Lapse Calculator
Plan a time lapse: frames and final clip length from interval, shooting time and frame rate, or shooting time from a target clip.
Open Time Lapse Calculator →Timecode to Frame Converter
Convert non-drop-frame timecode to a frame number and back, at 24, 25, 30, 50 or 60 frames per second.
Open Timecode to Frame Converter →Caesar Cipher Tool
Encode and decode text with a Caesar shift, with a brute-force view of all 25 shifts as a helper.
Open Caesar Cipher Tool →Vigenere Cipher Tool
Encode and decode text with the classical Vigenère cipher using a keyword, preserving case and punctuation.
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