Work out the monthly payment, total interest and payoff time for any loan, including extra monthly payments.
monthly payment
How to use this tool
Type how much you are borrowing, after any deposit.
Use the annual interest rate and the full term in years — 30 years is typical for a mortgage, 3–7 for a car or personal loan.
Under Advanced options, add any extra amount you plan to pay each month.
Compare the monthly payment, total interest and payoff time — and how much an extra payment saves.
Formula & worked example
A $200,000 loan at 6% over 30 years costs $1,199.10 per month, $431,676.38 in total and $231,676.38 in interest. Adding $200 a month shortens the loan and saves tens of thousands in interest.
Limitations — read this before you rely on it
This is a standard fixed-rate amortisation calculation. It does not include taxes, insurance, fees or variable-rate changes, which can change the real monthly cost — check your loan offer for those. An extra payment only helps if your lender applies it to principal without a prepayment penalty.
Frequently asked questions
From the loan amount, the monthly interest rate and the number of payments, using the amortisation formula. A higher rate or a longer term raises total interest even when the monthly payment falls.
It lowers the monthly payment but raises total interest — a 30-year loan costs far more in interest than a 15-year loan on the same amount.
Yes: every extra dollar goes to principal, so future interest is charged on a smaller balance and the loan ends sooner. Even $100 a month makes a large difference over 30 years.
Taxes, homeowner insurance, private mortgage insurance, origination fees and other charges are not in this figure — add them to the payment for the true monthly cost.
This calculator assumes a fixed rate. If your rate changes, re-run it with the new rate and the remaining balance and term.