pH / pOH Converter

About this calculator

This calculator converts between pH, pOH, hydrogen-ion concentration [H⁺], and hydroxide-ion concentration [OH⁻] at 25 °C, using pH = −log₁₀[H⁺], pOH = −log₁₀[OH⁻], and the relationship pH + pOH = 14 (since [H⁺][OH⁻] = Kw = 10⁻¹⁴ at that temperature). A solution is acidic when pH < 7, basic when pH > 7, and neutral at pH = 7.

Chemistry students and lab technicians use it to move quickly between whichever value they measured or were given and the others — for instance, converting a pH meter reading into ion concentration for a calculation, or checking pOH when working with basic solutions. Enter any one of the four values to instantly get the other three.