Calculate pOH from hydroxide concentration and convert to pH.
pOH mirrors pH for bases. Since the ion product of water fixes [H⁺][OH⁻] at 10⁻¹⁴ at 25 °C, either quantity determines the other completely. Working in pOH is more natural for basic solutions, and it avoids handling very small hydrogen ion concentrations.
pOH
pOH = −log₁₀[OH⁻]; pH = 14 − pOH at 25 °C
pOH = −log₁₀[OH⁻]; pH = 14 − pOH at 25 °C pOH mirrors pH for bases. Since the ion product of water fixes [H⁺][OH⁻] at 10⁻¹⁴ at 25 °C, either quantity determines the other completely.
Working in pOH is more natural for basic solutions, and it avoids handling very small hydrogen ion concentrations.
This calculator takes 1 input: Hydroxide ion concentration. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.