Titration Calculator — Find Unknown Concentration
Find the concentration of an unknown solution (analyte) from a titration experiment. Enter the known titrant concentration, the volume at the equivalence point, and the analyte volume — the calculator solves for C₂ using the general stoichiometric formula.
mol/L
mL
mL
Stoichiometric ratio (n₂ / n₁)
Concentration of the analyte at the equivalence point
- 1
C₁ × V₁
0.1 × 25 = 2.5Product of titrant concentration (mol/L) and volume (mL) — equals mmol at the equivalence point. - 2
Apply stoichiometric ratio × r
2.5 × 1 = 2.5 - 3
Divide by V₂ to get C₂
2.5 ÷ 20 = 0.12500
How does this calculator work?
At the equivalence point, C₂ = C₁ × V₁ × (n₂/n₁) / V₂. For a 1:1 reaction this is just C₁V₁ = C₂V₂. Enter the known titrant concentration and volume, the analyte volume, and the mole ratio from the balanced equation. The result is the unknown solution concentration in mol/L.
Formula
How this is calculated
Titration is a volumetric technique for determining the concentration of an unknown solution (the analyte) by reacting it quantitatively with a solution of known concentration (the titrant or standard solution). The titrant is added from a burette until the reaction reaches its equivalence point — typically signalled by an indicator colour change or a pH inflection — at which point stoichiometrically exact amounts of the two species have reacted.
At the equivalence point, the moles of titrant that reacted divided by the stoichiometric coefficient n₁ equals the moles of analyte divided by its coefficient n₂. Rearranging gives C₂ = C₁ × V₁ × (n₂/n₁) / V₂. For simple 1:1 reactions such as HCl + NaOH this reduces to C₁V₁ = C₂V₂. For polyprotic acids or polyvalent bases the ratio differs: H₂SO₄ reacting with NaOH is a 1:2 reaction (one mole of acid consumes two moles of base), so n₂/n₁ = 2.
This calculator assumes you have reached a true equivalence point, that the reaction goes to completion, and that volumes are measured accurately. Sources of error include indicator-endpoint overshoot, parallax reading of the burette meniscus, and temperature-dependent volume changes. For redox titrations the same formula applies once you identify n₁ and n₂ from the balanced half-reactions.
Frequently asked questions
The equivalence point is the theoretical moment when stoichiometrically exact amounts of titrant and analyte have reacted — no excess of either remains. The endpoint is when the indicator changes colour. A perfect indicator changes exactly at the equivalence point, but a slight overshoot (titration error) means the endpoint comes just after, introducing a small systematic error.
Change it whenever the balanced equation shows a ratio other than 1:1. For example, H₂SO₄ + 2 NaOH → Na₂SO₄ + 2 H₂O uses a 1:2 ratio (one mole of acid, two moles of base), so enter n₂/n₁ = 2 if NaOH is the analyte. For H₃PO₄ fully neutralised by NaOH, use 3. Check the balanced equation every time.
Yes — the formula is universal. Find the n₁ and n₂ values from the balanced redox half-reactions. For example, permanganate (MnO₄⁻, n=5) oxidising Fe²⁺ (n=1) gives a 1:5 ratio between titrant and analyte. Divide to get n₂/n₁ = 5 if Fe²⁺ is the analyte and permanganate is the titrant.
Also known as
TG we-Calculate Editorial Team. (2026). Titration Calculator — Find Unknown Concentration [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/titration-calculator
TG we-Calculate Editorial Team. "Titration Calculator — Find Unknown Concentration." TG we-Calculate. 2026. https://we-calculate.com/calculator/titration-calculator.
TG we-Calculate Editorial Team, "Titration Calculator — Find Unknown Concentration," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/titration-calculator
@misc{wecalculate_titration_calculator, title = {Titration Calculator — Find Unknown Concentration}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/titration-calculator}}, year = {2026}, note = {TG we-Calculate} }
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