Henderson–Hasselbalch Calculator

Calculate buffer pH using pH = pKa + log([A⁻]/[HA]) or solve for any variable.

⚗️ Henderson–Hasselbalch

pKa of Acid

[A⁻] Conjugate Base mol/L

[HA] Weak Acid mol/L

⚠ Enter valid values.

Henderson-Hasselbalch Equation

pH = pKa + log([A⁻]/[HA])

Buffer pH

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⚗️ Henderson–Hasselbalch Equation

pH = pKa + log([A⁻] / [HA])

This equation is key in biochemistry for designing buffer solutions. It relates the pH of a solution to the pKa of the acid and the ratio of concentrations of conjugate base to acid.

pKa = negative log of acid dissociation constant
[A⁻] = conjugate base concentration (e.g. acetate CH₃COO⁻)
[HA] = weak acid concentration (e.g. acetic acid CH₃COOH)

📖 Example

✅ Acetate Buffer

Acetic acid (pKa = 4.74), [CH₃COO⁻] = 0.1 M, [CH₃COOH] = 0.1 M

pH = 4.74 + log(0.1/0.1) = 4.74 + log(1) = 4.74 + 0 = 4.74

Equal concentrations → pH = pKa (half-equivalence point)

❓ FAQ

When is Henderson-Hasselbalch most accurate?

It's most accurate when pH is within 1 unit of pKa, i.e. pKa−1 ≤ pH ≤ pKa+1. Outside this range, the buffer capacity is too low.

What is a buffer solution?

A buffer resists changes in pH when small amounts of acid or base are added. It contains a weak acid and its conjugate base in similar concentrations.

🔗 Related

Comprehensive Guide

Mastering Henderson-Hasselbalch Calculations

Our free Henderson-Hasselbalch Calculator simplifies complex chemistry mathematics, providing step-by-step clarity for analytical problem solving. Whether you're prepping for an AP Chemistry exam or working in a research lab, computing Henderson-Hasselbalch quickly prevents cascading mathematical errors. Mastering the concepts behind Henderson-Hasselbalch is crucial for understanding advanced chemical reactions and laboratory procedures.

Why is Henderson-Hasselbalch Important?

In analytical chemistry, precision is everything. Having a reliable way to compute Henderson-Hasselbalch saves time, prevents wasted materials, and ensures scientific accuracy.

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Speed

Instant

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Accuracy

100%

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Level

All Levels

Always verify your input units before calculating. Mismatched units (e.g., using mL instead of L) are the most common source of error when determining Henderson-Hasselbalch!

Common Applications

Academic Study: Speeding up repetitive calculations.
Laboratory Practice: Ensuring exact stoichiometry for reactions.
Data Validation: Studying for college-level chemistry tests.

Relying solely on the calculator without understanding the underlying formula. Always review the step-by-step breakdown to internalize the mechanics.