Calculate Hardy-Weinberg equilibrium values for population genetics. Find allele frequencies, genotype frequencies, and carrier rates from any known value.
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The Hardy-Weinberg principle is fundamental to population genetics. This calculator helps you determine allele and genotype frequencies from any known value - whether it's the frequency of affected individuals, carriers, or either allele.
Hardy-Weinberg equilibrium describes how allele frequencies remain stable in a population when there's no evolution occurring. The equations p + q = 1 (for alleles) and p² + 2pq + q² = 1 (for genotypes) let us calculate all frequencies from just one known value.
Hardy-Weinberg Equations
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Learn and practice population genetics problems.
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Start from affected frequency, carrier rate, or allele frequency.
Get all allele and genotype frequencies from any single value.
Calculate expected numbers for any population size.
HW equilibrium assumes: no mutation, random mating, no gene flow, infinite population size, and no selection. Real populations rarely meet all conditions, but it provides a useful baseline for comparison.
Carriers are heterozygotes (Aa), with frequency 2pq. For rare recessive diseases, most disease alleles are carried by heterozygotes, not affected individuals (who are aa).
The math is exact given HW assumptions. Real-world accuracy depends on how well the population meets equilibrium conditions. Large, randomly mating populations with no recent selection give best results.
For recessive conditions, only homozygous recessive (aa = q²) individuals show the phenotype. If 1 in 10,000 people are affected, q² = 0.0001, so q = 0.01 and carrier frequency 2pq ≈ 2%.