pKa Calculator
Calculate pKa from pH and conjugate base/acid ratio, calculate buffer pH from pKa, or solve for the base/acid ratio with Henderson-Hasselbalch.
Quick answer: pH = pKa + log10(base / acid), so pKa = pH - log10(base / acid).
Result appears here.
Henderson-Hasselbalch pKa Formula
- pH: pH = pKa + log10(base / acid).
- pKa: pKa = pH - log10(base / acid).
- base/acid ratio: base / acid = 10^(pH - pKa).
This educational calculator assumes ideal buffer behavior. Activity, ionic strength, temperature, and buffer capacity can shift real measured pH.