pH Calculator

Molar concentration of the acid or base you dissolved, in moles per litre.

For a strong acid, 0.01 mol/L gives pH 2 exactly.

The acid dissociation constant — how readily the weak acid gives up a proton. Bigger Ka means a stronger, more acidic solution.

Acetic acid Ka ≈ 1.8×10⁻⁵.

The base dissociation constant — how readily the weak base grabs a proton and releases OH⁻. Bigger Kb means a more alkaline solution.

Ammonia Kb ≈ 1.8×10⁻⁵.

A measured pH value to work backwards from into [H⁺], [OH⁻] and pOH.

7 is neutral at 25 °C; below 7 is acidic, above 7 is basic.