pH / pOH Calculator

Instantly convert between pH, pOH, Hydrogen ion concentration [H⁺], and Hydroxide ion concentration [OH⁻].

Input Value

The pH scale

The pH scale measures how acidic or basic a substance is. It ranges from 0 to 14. A pH of 7 is neutral (like pure water). A pH less than 7 is acidic, and a pH greater than 7 is basic.

Key Formulas

pH = -log₁₀[H⁺]

pOH = -log₁₀[OH⁻]

pH + pOH = 14 (at 25°C)