Buffer Calculator

Design a buffer using the Henderson-Hasselbalch equation.

Buffer Parameters

pKa of weak acid

Target pH

Total buffer concentration (mol/L)

Total volume (mL)

Molar mass of acid form (g/mol)

Molar mass of base form (g/mol)

Molar masses are optional — fill in to also compute the mass to weigh.

Buffer Composition

Enter pKa, target pH, concentration, and volume to design the buffer.

Description

A buffer resists pH change when small amounts of acid or base are added. The Henderson-Hasselbalch equation relates pH, pKa, and the ratio of conjugate base (A⁻) to weak acid (HA): pH = pKa + log₁₀([A⁻]/[HA]).

How to use

Enter the pKa of the weak acid, the target pH, the total buffer concentration, and the total volume. The ratio [A⁻]/[HA], concentrations, and moles of each form are computed instantly. Optionally enter molar masses to also get the mass to weigh.