Skip to content
CalculatorGeek

Acid-Base pH Calculator

Updated Sep 2026 Used 0 times
Choose the species that supplies H⁺ or OH⁻.
Enter the analytical concentration of the strong acid or base.

Guest calculations stay on this device. Signed-in results sync privately.

Your result

Calculated pH

Enter your values, then calculate to see a verified result.

Inputs usedReview the information used for this result.
Full calculation and sourcesUses ideal, complete dissociation at 25 °C; review the assumptions before applying the result.

Versioned calculationFormula v1.0.0

25 °C water conventionUnit-normalized strong-electrolyte modelFormula v1.0.0
Public verification recordFormula v1.0.0
Review scope
Formula, Unit Normalization, Boundaries, Method Copy, And Related Routes
Review team
CalculatorGeek Algorithmic Team
Verified
2026-09-27
Next source review
2027-09-27
Automated fixtures
4 cases

Review method

Strong-acid and strong-base reference cases, unit-equivalent concentrations, zero/negative boundaries, and rendered formula labels reviewed separately.

Known limitations

  • Assumes a strong monoprotic acid or monobasic base and complete dissociation.
  • Uses pKw = 14.00 at 25 °C; temperature, activities, ionic strength, and polyprotic equilibria are outside scope.
  • For weak acids, buffers, or mixtures, use the dedicated chemistry workflow instead of forcing this model.

Primary sources

On this page

What this calculates

This page estimates pH and pOH from the analytical concentration of a strong monoprotic acid or monobasic base. It keeps the concentration in mol/L, applies the ideal 25 °C convention, and shows the ion concentration used.

Formula and steps

  1. Normalize the concentration to mol/L.
  2. For a strong acid, set [H⁺] equal to the concentration and calculate pH = −log10([H⁺]).
  3. For a strong base, set [OH⁻] equal to the concentration, calculate pOH, then use pH = 14.00 − pOH.

Use the Molarity Calculator when your starting data is a mass and final solution volume.

Assumptions and limits

The model is intentionally narrow: complete dissociation, one charged proton or hydroxide equivalent, ideal concentration behavior, and 25 °C water. It is not a weak-acid solver, buffer solver, titration curve, activity model, or safety assessment.

Frequently asked questions

Does this calculate weak-acid pH?

No. Use a weak-species or buffer model when dissociation is incomplete.

Why does temperature matter?

The pOH = 14 − pH shortcut uses the 25 °C water convention.

Sources

From the guide library

Latest Chemistry articles

View all articles

Chemistry

Molarity vs Molality

Compare molarity and molality by formula, denominator, units, temperature effect, and use case. Learn why conversion usually needs density.