About the pH & pOH Calculator

Convert between pH, pOH, [Hโบ], and [OHโป] using the standard acid-base relationships.

What it is

The pH & pOH Calculator converts between the four interrelated measures of acidity: pH, pOH, hydrogen ion concentration [Hโบ], and hydroxide ion concentration [OHโป]. It uses pH + pOH = 14 and [Hโบ][OHโป] = Kw at 25ยฐC, with Kw adjustable for other temperatures. A strong acid/base mode derives pH directly from a molar concentration, assuming full dissociation.

Features

Four-way conversion

Enter any one of pH, pOH, [Hโบ], [OHโป] to get the other three.

Strong acid/base mode

Enter a molar concentration directly to get pH, assuming full dissociation.

Temperature-adjustable Kw

Adjust Kw for conditions other than the standard 25ยฐC.

Visual acid-base scale

See at a glance where your solution falls between acidic and basic.

Ready to use it?

Free, no sign-up required.

Open the pH & pOH Calculator