💧 Titration

Written and maintained by the PhDino author · Last reviewed 21 September 2026 · Checked against 2 independent reference calculations · how PhDino checks its numbers

Finding the volume of titrant needed to exactly neutralize a known amount of acid or base.

Titration is a way of measuring an unknown quantity (or checking a known one) by slowly adding a solution of precisely known concentration — the titrant — until the reaction between it and the sample is exactly complete. That point is the equivalence point: the moles of titrant added exactly match what the reaction stoichiometry requires to fully react with the sample.

For a simple monoprotic acid-base reaction, the mole ratio at equivalence is one-to-one, so equal moles of acid and base have reacted; other reactions (a diprotic acid, for instance) need twice as much base per mole of acid, which is what the acid-to-base mole ratio in this calculator accounts for.

Key formula

Moles of acid = acid concentration × acid volume
Moles of titrant needed = moles of acid ÷ acid:base mole ratio
Volume of titrant = moles of titrant needed ÷ titrant concentration

Notes & limitations

• In practice, the equivalence point is located experimentally with an indicator (a dye that changes color near the expected pH) or a pH meter, and read as the volume where that change happens — this calculation gives the expected volume to look for, not a substitute for actually running the titration.
• The point where an indicator visibly changes color (the "endpoint") and the true chemical equivalence point aren't always exactly the same — choosing an indicator that changes color close to the expected equivalence pH keeps the two close together.