Buffer pH Calculator (Henderson-Hasselbalch)

Find buffer pH from pKa and the acid/base ratio.

pH 4.76

Formula: pH = pKa + log₁₀([A⁻] ÷ [HA])

Step-by-step with your numbers:
1. Values used:
2. pKa = 4.76
3. [Conjugate base] A⁻ = 0.1 M
4. [Acid] HA = 0.1 M
5.
6. pKa x [Conjugate base] A⁻ = 4.76 x 0.1 = 0.476
7. pH = (pKa x [Conjugate base] A⁻) / [Acid] HA = 0.476 / 0.1 = 4.76
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The Henderson-Hasselbalch equation gives a buffer's pH.

The math behind it

pH = pKa + log₁₀([conjugate base] ÷ [acid]). When they're equal, pH = pKa.

Worked example

pKa 4.76, equal concentrations → pH 4.76.

FAQ

Best buffering?

Near the pKa, where the ratio is close to 1:1.