pH Calculator
How to calculate pH
- Choose what you know: pH, [H⁺], pOH, [OH⁻], or the concentration of a strong or weak acid or base.
- Type the value, and for a weak acid or base, its pKa or pKb.
- The pH, pOH, [H⁺] and [OH⁻] appear, along with whether the solution is acidic, neutral or basic.
Frequently asked questions
At what temperature is this?
25 °C, where pH + pOH = 14.
How is a weak acid handled?
The equilibrium is solved exactly with the quadratic formula rather than with the usual approximation, so it also works for dilute or fairly strong weak acids.