pH Calculator
Convert between pH, pOH, [H⁺] and [OH⁻] at 25 °C; also estimates pH of weak acids from Ka.
How to use the pH Calculator
- Fill in what you know of: pH, [H⁺], pOH, [OH⁻] — leave the unknown empty.
- The results (pH, pOH, [H⁺], [OH⁻], Solution is) are calculated instantly as you type.
- Use “Copy link” to share the calculation with the same input values.
Formula
- pH = −log₁₀[H⁺]
- pH + pOH = 14 (25 °C)
About this tool
Fill in one field; the first filled field is used.