Frequently Asked Questions

The Hardy-Weinberg equation, p² + 2pq + q² = 1, describes the expected genotype frequencies in a population that is not evolving, where p and q are the frequencies of the two alleles at a gene locus.

p is the frequency of the dominant allele and q is the frequency of the recessive allele. Together, p + q = 1 for a gene with two alleles.

p² is the expected frequency of homozygous dominant individuals (AA), 2pq is the expected frequency of heterozygous individuals (Aa), and q² is the expected frequency of homozygous recessive individuals (aa).

Use the 'From Genotype Counts' mode: enter observed AA, Aa, and aa counts. The calculator computes allele frequencies, expected genotype counts, and a chi-square statistic to test for equilibrium.

The chi-square statistic compares observed genotype counts to the counts expected under Hardy-Weinberg equilibrium. If it exceeds the critical value (3.841 at α=0.05, df=1), the population deviates significantly from equilibrium.

It assumes no mutation, no migration, random mating, no natural selection, and a very large population size. Real populations rarely meet all these assumptions perfectly.

Deviations from equilibrium can indicate natural selection, non-random mating, genetic drift, migration, or mutation acting on the population.

This calculator handles the standard two-allele case. Multi-allele Hardy-Weinberg extensions require additional terms not covered here.

The carrier frequency for a recessive trait is the heterozygote frequency, 2pq — the proportion of the population carrying one copy of the recessive allele without expressing the trait.

Yes, the Hardy-Weinberg calculator is completely free with no sign-up, and all calculations run instantly in your browser.