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Neutralisation Calculator

Work out neutralisation instantly with clear inputs, formula shown and shareable results.

About Neutralisation Calculator

Neutralisation reaches its end point when the moles of donated protons equal the moles of hydroxide supplied. Moles of acid come from concentration times volume, multiplied by the protons each molecule can donate, so a diprotic acid needs twice the base a monoprotic one does at the same concentration. 25 mL of 0.1 M monoprotic acid needs 20 mL of 0.125 M base.

Formulas

Proton balance

C(acid) x V(acid) x protons = C(base) x V(base)

Base volume

V(base) = moles of H+ / C(base)

Worked example

With the default values below, Neutralisation Calculator returns Base Needed To Neutralise of 20.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Acid concentrationminimum 0 mol/L
0.1 mol/L
Acid volumeminimum 0 mL
25 mL
Base concentrationminimum 0 mol/L
0.125 mol/L
Protons donated per acid moleculeminimum 1
1

Results

Base Needed To Neutralise
20.00 mL
Moles Of Acid Present
2.5000 × 10⁻³
Moles Of Base Required
2.5000 × 10⁻³
Base Volume Per Unit Acid Volume
0.8000

Step by step

  1. 1Values used
  2. 2Proton balance
  3. 3Base volume
  4. 4Base Needed To Neutralise= 20.00 mL
  5. 5Moles Of Acid Present= 0.0025
  6. 6Moles Of Base Required= 0.0025
  7. 7Base Volume Per Unit Acid Volume= 0.8000

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Does the end point mean pH 7?

Only for a strong acid with a strong base. A weak acid neutralised by a strong base reaches equivalence above pH 7 because the conjugate base hydrolyses.

Why does the proton count matter?

Sulfuric acid donates two protons per molecule, so 0.1 M sulfuric acid neutralises twice as much base as 0.1 M hydrochloric acid.

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