Calculate the frequencies of alleles A and a from the numbers of AA, Aa, and aa individuals in a diploid population.
| Individuals (N) | – |
| Frequency p (A) | – |
| Frequency q (a) | – |
Use this calculator to determine allele frequencies at a single genetic locus when you know the numbers of individuals with genotypes AA, Aa, and aa.
This calculator assumes a diploid population with two possible alleles at the locus: A and a. Each individual carries two copies of the locus, so the population has 2N total alleles, where N is the number of individuals.
The frequency of allele A (p) is calculated as (2 × AA + Aa) / (2 × N). Each AA individual contributes two A alleles, while each Aa individual contributes one A allele. The frequency of allele a (q) is calculated as (2 × aa + Aa) / (2 × N).
Because only A and a are considered, p + q = 1. Allele frequencies range from 0 to 1 and can also be expressed as percentages by multiplying them by 100.
AA count: Number of individuals with genotype AA. Each contributes two copies of allele A.
Aa count: Number of individuals with genotype Aa. Each contributes one copy of allele A and one copy of allele a.
aa count: Number of individuals with genotype aa. Each contributes two copies of allele a.
Individuals (N): Total number of individuals in the population, calculated as AA + Aa + aa.
Frequency p (A): Frequency of allele A among all copies of the locus in the population.
Frequency q (a): Frequency of allele a among all copies of the locus in the population.
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