Buffer Calculator

Calculate the pH of a buffer solution using the Henderson-Hasselbalch equation.

pKa or Ka

pKa Value

Ka (M)

Concentrations (M)

[Conjugate Base]

[Weak Acid]

Enter inputs to calculate pH

Scientific Note

The Henderson-Hasselbalch equation is valid when the concentrations of the weak acid and conjugate base are relatively high compared to the Ka value. At the midpoint of a titration, pH = pKa because [Base] = [Acid].