Henderson-Hasselbalch Calculator

What is Henderson-Hasselbalch Calculator?

The Henderson-Hasselbalch calculator uses the Henderson-Hasselbalch equation to calculate pH, pKa, or buffer component concentrations. This equation relates the pH of a buffer solution to the pKa of the weak acid and the ratio of conjugate base to acid concentrations, making it essential for buffer preparation in biochemistry and molecular biology.

How to Use This Calculator

1. Select a common acid from the dropdown (optional) or enter pKa manually
2. Enter three of the four values (pH, pKa, [A⁻], [HA])
3. Leave one field blank - this will be calculated
4. Click Calculate to get your result

When to Use

This calculator is useful when you need to:

• Prepare buffer solutions with specific pH values
• Calculate buffer component ratios for optimal buffering capacity
• Determine pKa from pH and concentration measurements
• Design buffers for enzyme assays, protein purification, or cell culture

Example Calculation

For an acetate buffer at pH 5.00:

Result: [HA] ≈ 0.058 M

Understanding the Equation

The Henderson-Hasselbalch equation:

Where [A⁻] is the concentration of conjugate base and [HA] is the concentration of the weak acid. The equation is most accurate when pH is within ±1 unit of pKa.

FAQ

Q: What is the Henderson-Hasselbalch equation used for?
A: It's used to calculate the pH of buffer solutions and to prepare buffers with specific pH values for laboratory applications.

Q: When is the equation most accurate?
A: The equation works best when the pH is within ±1 unit of the pKa value, providing the most effective buffering capacity.