How to Calculate pH: Formula, Steps & Examples
Learn how to calculate pH — the formula explained step by step, with worked examples and a free calculator to check your answer.
pH Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
pH
7.00
- pOH
- 7.00
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the pH Calculator
The pH Calculator works out your ph, along with 1 related figure in an instant. Enter hydrogen ion concentration [h⁺] and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the hydrogen ion concentration [h⁺].
- Read off your ph, together with poh — the calculator updates automatically, with no button to press.
Worked example
For example, with hydrogen ion concentration [h⁺] of 0 mol/L, the ph is 7.00.
| Hydrogen ion concentration [H⁺] | 0 mol/L |
|---|
| pH | 7.00 |
|---|---|
| pOH | 7.00 |
Results are estimates for educational use, not professional advice.
Frequently asked questions
pH is the negative base-10 logarithm of the hydrogen ion concentration: pH = −log₁₀[H⁺]. A concentration of 1 × 10⁻⁷ mol/L gives a pH of 7.
pH runs from 0 to 14. Below 7 is acidic, 7 is neutral and above 7 is basic (alkaline).
pOH measures hydroxide ion concentration. At 25°C, pH + pOH = 14, so the calculator derives pOH from the pH.
The scale is logarithmic, so each whole pH unit is a tenfold change in hydrogen ion concentration.
Enter the hydrogen ion concentration [h⁺]. Read off your ph, together with poh — the calculator updates automatically, with no button to press.