Calculate equilibrium genotype frequencies and expected counts from allele frequency p and population size.
| Frequency q (a) | – |
| P(AA) | – |
| P(Aa) | – |
| P(aa) | – |
| Expected AA | – |
| Expected Aa | – |
| Expected aa | – |
Use this calculator for a two-allele Hardy–Weinberg check: you know how common allele A is in a population of size N and want the equilibrium genotype frequencies and expected counts for AA, Aa, and aa.
Enter p as a percent (50 for p = 0.50). Then q = 1 − p, P(AA) = p², P(Aa) = 2pq, and P(aa) = q². Expected counts multiply those frequencies by N. The calculation assumes random mating, no selection, no migration, no mutation, and a large population.
This is the ideal equilibrium mix. Real populations can deviate; the calculator does not run a statistical test for Hardy–Weinberg equilibrium.
Frequency of A (p): How common allele A is, as a percent. Type 40 for p = 0.40.
Population size N: How many individuals the expected counts are scaled to.
Frequency q (a): Frequency of the other allele, 1 − p.
P(AA), P(Aa), P(aa): Equilibrium genotype frequencies.
Expected AA, Aa, aa: Those frequencies multiplied by N.
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