Acids, equilibrium & kinetics · SL/HL
pH & Hydrogen Ion Concentration Calculator
Choose the direction of calculation. Concentration is in mol dm⁻³.
Your values
Start with the example or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Step-by-step working
The formula
pH = −log₁₀[H⁺]
[H⁺] = 10⁻ᵖᴴ
| Symbol | Meaning |
|---|---|
| [H⁺] | Hydrogen-ion concentration used by the course model. |
When to use this calculator
The logarithmic scale means a change of one pH unit corresponds to a factor of ten in [H⁺].
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- pH = −log₁₀[H⁺] = −log₁₀(0.001) = 3
pH = 3
Common mistakes
- Do not use natural logarithm for the pH definition.