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Allele Frequency Calculator

Hardy-Weinberg allele and genotype frequencies from q.

Introduction

Allele Frequency Calculator — Hardy-Weinberg allele and genotype frequencies from q. Enter Recessive allele frequency (q) to get an instant, accurate result.

Formula

Under Hardy-Weinberg equilibrium, the two allele frequencies at a gene locus sum to 1: p + q = 1. Given the recessive allele frequency q, the dominant allele frequency is p = 1 − q, and the expected genotype frequencies follow p² (AA), 2pq (Aa), q² (aa).

Step-by-step

  1. Enter the Recessive allele frequency (q).
  2. Click Calculate to see your result instantly.

Real-world example

Example: With Recessive allele frequency (q) = 0.3, the Allele Frequency Calculator gives P: 0.7, Q: 0.3, P2: 0.49.

Frequently Asked Questions

Where does the value of q usually come from?
q is often estimated from the observed frequency of the recessive phenotype in a population, since recessive individuals (aa) are the only genotype whose frequency equals q² directly.
Do p and q always add up to 1?
Yes, for a gene with exactly two alleles, p and q are defined as complementary proportions of the total allele pool, so p + q = 1 by definition.
What inputs does the Allele Frequency Calculator need?
You'll need to provide: Recessive allele frequency (q). All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Allele Frequency Calculator?
The Allele Frequency Calculator applies the formula exactly as calculated — Under Hardy-Weinberg equilibrium, the two allele frequencies at a gene locus sum to 1: p + q = 1. Given the recessive allele frequency q, the dominant allele frequency is p = 1 − q, and the expected genotype frequencies follow p² (AA), 2pq (Aa), q² (aa). — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Allele Frequency Calculator free to use?
Yes, the Allele Frequency Calculator is completely free, requires no signup, and runs instantly in your browser.

About the Allele Frequency Calculator

The Allele Frequency Calculator uses a real, verifiable formula — Under Hardy-Weinberg equilibrium, the two allele frequencies at a gene locus sum to 1: p + q = 1. Given the recessive allele frequency q, the dominant allele frequency is p = 1 − q, and the expected genotype frequencies follow p² (AA), 2pq (Aa), q² (aa). — so results are accurate every time, not an approximation.