Solve titration problems — unknown concentration, unknown volume or moles reacted — with stoichiometric ratios.
Needed when solving for concentration or moles.
Needed only when solving for unknown volume.
How to use this tool
Unknown concentration, unknown volume, or moles reacted — the other values do the work.
Its concentration and the volume used, in mol/L or mmol/L and mL or L.
The volume (or concentration) you measured, plus the mole ratio from the balanced equation under Advanced options.
The big number is the missing quantity, with moles of the known substance shown for checking.
Formula & worked example
Worked example: 25.0 mL of 0.100 mol/L NaOH neutralises 20.0 mL of HCl in a 1:1 reaction. Moles of NaOH = 0.100 × 0.0250 = 0.00250 mol, so moles of HCl = 0.00250 mol and its concentration = 0.00250 ÷ 0.0200 = 0.125 mol/L.
Limitations — read this before you rely on it
This calculator finds the equivalence point from a balanced equation and ideal volumes; real titrations have indicator error, endpoint overshoot, dilution effects and activity corrections, and it assumes the reaction goes to completion in the stated ratio.
Frequently asked questions
A method for finding an unknown concentration by slowly adding a solution of known concentration until the reaction just completes — the equivalence point — then working backwards from the volume used.
Multiply the known concentration by its volume to get moles, adjust by the mole ratio from the balanced equation, then divide by the unknown volume. This calculator does each step and shows the moles for checking.
The moment when the reactants have combined exactly in the ratio of the balanced equation — no excess of either side. Indicators or pH meters signal it, though the visible endpoint is usually a touch past it.
Not every reaction is 1:1. One mole of sulfuric acid neutralises two of sodium hydroxide, so ignoring the 1:2 ratio would halve or double your answer. Enter both coefficients under Advanced options.
Yes — this calculator converts everything to mol/L and litres first, so any mix of mmol/L, mol/L, mL and L gives the same answer.