chemistry

Buffer pH Calculator

Use Henderson–Hasselbalch for an acid/conjugate-base buffer, including strong acid/base addition and dilution.

Calculator

Formula

pH=pKₐ+log([A⁻]/[HA])

Assumptions and limits

Both buffer components must remain after neutralization; activity effects are neglected.

Example

Editable worked example

The calculator starts with an editable example.

Sources

Chemistry 2e — OpenStax

Frequently asked questions

Are my inputs uploaded?

No. This calculator runs locally in your browser. Inputs are placed in a URL only when you explicitly copy a share link.

Why are units converted first?

Canonical units prevent scale errors when inputs use mixed units. The result is converted back to your selected output unit afterward.

Does the result replace professional judgment?

No. The result applies only to the stated model and assumptions. Qualified people should review high-risk engineering, medical, or laboratory decisions.