Buffer pH Calculator

Calculate pH of buffer solutions using the Henderson-Hasselbalch equation. Input acid/base concentrations and pKa to find buffer pH.

Calculator

Concentration of the weak acid in mol/L

Concentration of the conjugate base in mol/L

Acid dissociation constant (pKa) of the weak acid

Results

Enter values and click Calculate to see results

About Buffer Solutions

Buffer solutions are solutions that resist changes in pH when small amounts of acid or base are added.

Henderson-Hasselbalch Equation:

pH = pKa + log₁₀([A⁻]/[HA])

Where:

  • pH is the pH of the buffer solution
  • pKa is the acid dissociation constant of the weak acid
  • [A⁻] is the concentration of the conjugate base
  • [HA] is the concentration of the weak acid

Buffer Capacity:

  • Maximum when [A⁻] = [HA] (pH = pKa)
  • Effective range: pKa ± 1
  • Higher total concentration increases buffer capacity

Applications:

  • Biological systems (blood, cells)
  • Laboratory procedures
  • Industrial processes
  • Food preservation
  • Medical treatments