Genotype Frequency Calculator

Work out genotype frequency instantly with clear inputs, formula shown and shareable results.

About Genotype Frequency Calculator

Converts an allele frequency into expected genotype counts for a population of the stated size under Hardy-Weinberg equilibrium.

Formula

Expected genotype counts

Counts = population x p^2, 2pq and q^2 for the three genotypes

Worked example

With the default values below, Genotype Frequency Calculator returns Expected heterozygotes of 240.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Dominant allele frequencyaccepts 0.001–0.999: 0.6
Population sizeaccepts 1–10,000,000: 500

Results

Expected heterozygotes: 240.00
Expected homozygous dominant: 180.00
Expected homozygous recessive: 80.00
Expected dominant phenotype: 420.00

Step by step

1Values used
2Expected genotype counts
3Expected heterozygotes= 240.00
4Expected homozygous dominant= 180.00
5Expected homozygous recessive= 80.00
6Expected dominant phenotype= 420.00

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why do heterozygotes peak at p = 0.5?

The 2pq term is maximised at equal allele frequencies, where half the population is heterozygous.

Can rare alleles hide in heterozygotes?

Yes. At q = 0.01 there are about 198 carriers for every affected homozygote.