pH Calculator
Enter any one value - pH, pOH, hydrogen ion concentration or hydroxide ion concentration - and get all the others.
| Quantity | Value |
|---|---|
| pH | |
| pOH | |
| [H+] (mol/L) | |
| [OH-] (mol/L) |
How to use
- Choose which value you know from the dropdown.
- Type the value. For concentrations use mol/L, for example 0.001 or 1e-3.
- All four quantities are calculated at once, with the acid/base classification.
Note
The relations used are pH + pOH = 14 and [H+][OH-] = 1e-14 at 25°C. Values outside the 0 to 14 pH range are possible for very strong acids and bases and are shown with a warning.
Frequently Asked Questions (FAQ)
What does this pH calculator calculate?
pH, pOH, hydrogen ion concentration and hydroxide ion concentration. Enter any one value and get all four, with the acid or base classification.
How do I enter a concentration?
Type it in mol/L, for example 0.001 or 1e-3.
How do pH and pOH relate?
They follow pH + pOH = 14 and [H+][OH-] = 1e-14 at 25 degrees Celsius.
What happens with very strong acids or bases?
pH values outside the 0 to 14 range are possible and are shown with a warning.