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pH & pOH Calculator

Convert between pH, pOH, [H⁺] and [OH⁻] — enter any one value and get the other three with the log algebra shown.

Calculator

Results update as you type. Every step of the working is shown below.

Examples:

Defaults to 25 °C (Kw = 1.0×10⁻¹⁴).

Result

Enter values above — the answer appears here instantly, with full working.

Formula used

pH = −log₁₀[H⁺] · pOH = −log₁₀[OH⁻] · pH + pOH = pKw

Every result substitutes your values into this relation step by step above.

Assumptions

  • Concentrations stand in for activities — exact for dilute solutions only.
  • Kw depends on temperature: 25 °C default; other temperatures use a linearized pKw.

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