🧪 Titration Calculator
Enter the known concentration, the titrant volume used, the analyte volume and the mole ratio to get the unknown concentration.
Unknown concentration
0.125 M
At the equivalence point of a titration, the moles of acid and base are stoichiometrically equal: C₁V₁ × (mole ratio) = C₂V₂. So the unknown concentration = known C × known V × (mole ratio) ÷ unknown V. The mole ratio is 1 for a 1:1 reaction like HCl + NaOH, 2 when the unknown supplies twice the reactive units (e.g. a diprotic acid neutralising a monoprotic base). Volumes can be in any matching unit. 🔒 In your browser.
How the titration calculator works
At the equivalence point of an acid–base titration, the reacting moles are stoichiometrically balanced: (known concentration × known volume) × mole ratio = unknown concentration × unknown volume. Rearranged, the unknown concentration = C_known × V_known × (mole ratio) ÷ V_unknown. The mole ratio is 1 for a 1:1 reaction like HCl + NaOH, and accounts for polyprotic acids or bases otherwise.
Volumes can be in any consistent unit (they cancel), so millilitres in gives molarity out. The mole ratio is the coefficient of the unknown divided by the coefficient of the known in the balanced neutralisation — 2 for a diprotic acid (like H₂SO₄) titrated with a monoprotic base. This finds the concentration at the equivalence point; it doesn't compute the titration-curve pH.
Frequently asked questions
How do you calculate concentration from a titration?
Use the equivalence relationship C₁V₁ × (mole ratio) = C₂V₂. Solve for the unknown: C_unknown = C_known × V_known × mole ratio ÷ V_unknown. For a 1:1 acid–base reaction, that's simply C₁V₁ = C₂V₂.
What is the equivalence point?
The point in a titration where the added titrant has exactly neutralised the analyte — the moles of acid and base are stoichiometrically equal. An indicator or pH meter marks it; the volume there is what you enter as the known volume.
What is the mole ratio in a titration?
The ratio of the reacting moles from the balanced equation — the unknown's coefficient divided by the known's. It's 1 for HCl + NaOH, but 2 for a diprotic acid like H₂SO₄ reacting with NaOH (H₂SO₄ + 2NaOH), because each acid supplies two H⁺.
Do the volume units matter?
No, as long as both volumes use the same unit — they cancel in the ratio. Enter both in mL (or both in L) and the concentration comes out in the same units as the known concentration.
Does this give the pH during the titration?
No — it finds the unknown concentration at the equivalence point. Plotting the pH through the titration (the titration curve) needs the weak-acid/base equilibrium tools, since pH depends on the acid/base strength.