Hardy-Weinberg Equilibrium Calculator

Set the allele frequency p (dominant allele A). The bars show the three genotype frequencies a population at equilibrium would have: p² (AA), 2pq (Aa), q² (aa).

■ AA ■ Aa (heterozygote) ■ aa

p (freq. of A)0.50

q (freq. of a)0.50

p² AA0.25

2pq Aa0.50

q² aa0.25

allele freq p 0.50

Try: slide p to 0.10. Notice the recessive phenotype (q²) is only ~0.81 yet carriers (2pq ≈ 0.18) far outnumber affected homozygotes — that is why rare recessive alleles persist hidden in heterozygotes.