Chemistry
Henderson-Hasselbalch Calculator
Henderson-Hasselbalch Calculator calculate buffer pH from acid pKa and conjugate-base-to-acid concentration ratio.
Chemistry
Henderson-Hasselbalch Calculator
Calculate buffer pH from acid pKa and conjugate-base-to-acid concentration ratio.
Formula
pH = pKa + log10([conjugate base] / [weak acid]).
About the Henderson-Hasselbalch Calculator
Calculate buffer pH from acid pKa and conjugate-base-to-acid concentration ratio.
How the Henderson-Hasselbalch Calculator Works
Positive base and acid concentrations are reduced to their ratio before its base-10 logarithm is added to the entered acid dissociation pKa.
Formula
pH = pKa + log10([conjugate base] / [weak acid]).
The calculation runs in your browser. Values are validated for required ranges, compatible units, and method-specific restrictions before results are displayed.
Required Inputs
- Acid pKa (required).
- Conjugate-base concentration (required).
- Weak-acid concentration (required).
Results Reported
The result panel reports the final answer and the intermediate quantities needed to check the calculation:
- Estimated buffer pH
- Base-to-acid ratio
- pH minus pKa
- Conjugate-base fraction (%)
Henderson-Hasselbalch Calculator Example
Select Example Data in the calculator to load this reproducible input set:
| Input | Example value |
|---|---|
| Acid pKa | 4.76 |
| Conjugate-base concentration | 0.2 |
| Weak-acid concentration | 0.1 |
How to Use the Calculator
- Confirm that the calculator title and formula match the quantity you need.
- Enter every required value using the unit shown with its field.
- Select Example Data to inspect a valid input set, or enter your own values and select Calculate.
- Review all reported values and the displayed formula before using the answer.
- Use Copy Result or Download CSV when you need a reusable record.
Accuracy and Limitations
This approximation is best for buffers where both forms are appreciable and activities are close to concentrations. It does not replace full equilibrium or ionic-strength treatment.
Keep units consistent, use measurements that represent the actual situation, retain full precision during the calculation, and round only the final answer. Professional decisions may require current official rules, field measurements, laboratory methods, or specialist review.
Frequently Asked Questions
What does the Henderson-Hasselbalch Calculator calculate?
Calculate buffer pH from acid pKa and conjugate-base-to-acid concentration ratio.
Which formula does the Henderson-Hasselbalch Calculator use?
pH = pKa + log10([conjugate base] / [weak acid]). Positive base and acid concentrations are reduced to their ratio before its base-10 logarithm is added to the entered acid dissociation pKa.
What should I check before using the Henderson-Hasselbalch Calculator result?
This approximation is best for buffers where both forms are appreciable and activities are close to concentrations. It does not replace full equilibrium or ionic-strength treatment.