Enter your genotype counts for AA, Aa, and aa into the Hardy-Weinberg Equilibrium Calculator to get your allele frequencies (p and q) alongside expected genotype frequencies — p², 2pq, and q² — and check if your population is in equilibrium.
Allele p frequency
--
Allele q frequency
--
Expected AA (p²)
--
Expected Aa (2pq)
--
Expected aa (q²)
--
Total population
--
Hardy-Weinberg equilibrium describes a theoretical state where allele frequencies remain constant across generations in a population. This occurs when there's no mutation, migration, selection, or genetic drift, and mating is random.
For allele p: p = (2×AA + Aa) / (2×N), where N is total population. For allele q: q = (2×aa + Aa) / (2×N). Since p + q = 1, you can also calculate q = 1 - p.
If allele frequencies are p and q, then expected genotype frequencies are: AA = p², Aa = 2pq, and aa = q². These represent the theoretical distribution assuming random mating.
Yes, if you have dominant and recessive phenotype counts. The frequency of the recessive allele (q) can be calculated as the square root of the recessive phenotype frequency: q = √(recessive/total).
Deviations from Hardy-Weinberg expectations suggest that one or more assumptions are violated. This could indicate natural selection, inbreeding, population structure, or other evolutionary forces acting on the population.
For scientific purposes, calculate to at least 4 decimal places. Small populations may show more variation due to genetic drift, while large populations should more closely approximate theoretical expectations.
Larger samples provide more accurate estimates. For meaningful results, aim for at least 50-100 individuals, though statistical power increases significantly with larger sample sizes of 500+ individuals.