Genetics & evolution · HL
Hardy–Weinberg
Relate allele and genotype frequencies under equilibrium.
Your values
Number formats & units
Use decimal dots in datasets. Single values also accept decimal commas and scientific notation such as 1.2e-3 or 1.2 × 10⁻³.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Download results
Excel and CSV files can be imported into Google Sheets.
More results
Show calculation steps
Interpretation & assumptions
Copy & export
Formula & example
The relationship
What the variables mean
| Symbol | Meaning |
|---|---|
| Allele frequencies. | |
| Predicted genotype frequencies at equilibrium. |
Worked example
- Known quantity
- Recessive genotype frequency q²
- Known frequency
- 0.16
p = 0.6, q = 0.4
Follow the example steps
- p + q = 1 → p = 0.6, q = 0.4
- p² = 0.36
- 2pq = 0.48
- q² = 0.16
- Check: p² + 2pq + q² = 1
Common mistakes
A dominant phenotype includes both AA and Aa.
Incorrect approach
q² = 0.09: dominant phenotype frequency = p² = 0.49
Correct approach
q = 0.3, p = 0.7: p² + 2pq = 0.49 + 0.42 = 0.91
More checks before you submit
- A dominant phenotype frequency is p² + 2pq, not p² alone.
Method notes
The equilibrium prediction depends on assumptions such as random mating and absence of strong evolutionary forces.