Allele Frequency Calculator
Enter the counts of AA, Aa, and aa genotypes to compute dominant and recessive allele frequencies (p and q) and total allele counts, with a population-genetics reference table.
Input Data
Results
At a glance:Enter the counts of AA, Aa, and aa genotypes to compute dominant and recessive allele frequencies (p and q) and total allele counts, with a population-genetics reference table.
Formula
p = (2×AA + Aa) ÷ (2×total).
q = (2×aa + Aa) ÷ (2×total).
p + q = 1.
$$p = \dfrac{2N_{AA} + N_{Aa}}{2N}$$$$q = \dfrac{2N_{aa} + N_{Aa}}{2N}$$How to Use
- Enter the counts of AA, Aa, and aa individuals in the population.
- The calculator returns p, q, total individuals, and allele totals.
- Use p and q with the Hardy-Weinberg calculator to get expected genotype frequencies.
FAQ
Why multiply the individual count by 2?
Humans and many organisms are diploid, carrying two alleles at a given locus per individual. So N individuals have 2N alleles in total, and the denominator for frequency must be 2N.
How are heterozygotes (Aa) counted?
Each Aa individual carries one dominant and one recessive allele, so it is counted once in both the dominant and the recessive allele totals. That is also why it is not multiplied by 2 in the formula.
What is the difference between allele frequency and genotype frequency?
Genotype frequency is the proportion of each of the three genotypes (AA, Aa, aa). Allele frequency breaks them down to the level of single alleles (A or a). This calculator derives allele frequencies from genotype counts.
Can the resulting p and q be used directly in Hardy-Weinberg?
Yes. After obtaining p and q, plug them into the Hardy-Weinberg equilibrium calculator to get the theoretical genotype frequencies (p², 2pq, q²), then compare with the observed distribution to judge whether the population is at equilibrium.
Does this method apply to any organism?
It applies to diploid organisms at a single locus with exactly two alleles. For multiple alleles, sex linkage, or polyploids, the corresponding extended formulas are needed.
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References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.