pH Calculator
Convert between hydrogen ion concentration, pH, and pOH.
- pH7
- pOH7
- [H+] concentration (mol/L)1.000e-7 mol/L
Enter a pH, pOH, or hydrogen ion concentration [H+] and this tool computes the other two values instantly.
How to use
- Choose which value you already know.
- Enter that value in the field.
- Read the pH, pOH, and [H+] results below.
Frequently asked questions
- How are pH and pOH related?
- At 25°C, pH + pOH = 14. So once you know one, the other follows by subtraction.
- What is pH in terms of [H+]?
- pH is the negative base-10 logarithm of the hydrogen ion concentration: pH = −log₁₀[H+].