Hardy-Weinberg Equilibrium Calculator
Calculate genotype frequencies from allele frequencies under Hardy-Weinberg equilibrium.
The assumptions matter more than the arithmetic
Hardy-Weinberg describes a population with no selection, no mutation, no migration, random mating and infinite size. No real population meets all five, which is precisely what makes the model useful: measuring how far observed frequencies depart from it is how population geneticists detect selection at work.
Why carriers vastly outnumber affected individuals
For a recessive disease affecting 1 in 10,000 people, q² = 0.0001 so q = 0.01, and carrier frequency 2pq is about 1.98% — nearly 200 carriers for every affected person. That ratio is the reason recessive conditions persist in populations despite strong selection against them.
Reproducibility depends on the inputs
The arithmetic here is exact; the measurements feeding it usually are not. Pipetting error, incomplete mixing and drift in a spectrophotometer all propagate straight through. Where a result matters, run it in duplicate and compare rather than trusting a single reading.
The formula
p² + 2pq + q² = 1, where p + q = 1
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Hardy-Weinberg Equilibrium Calculator
- Fill in each field with your own figures — the defaults are only there as an example.
- The result updates as you type, so there is no button to press.
- Check the breakdown under the main result for the supporting numbers.
- Use the copy button to take the result with you, or share the link to reload the same inputs.
Hardy-Weinberg Equilibrium Calculator — frequently asked questions
Is this hardy-weinberg equilibrium calculator free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
How accurate is the result?
The maths is exact for the formula shown on the page. Accuracy in the real world depends on your inputs and on assumptions the formula cannot see, so treat the output as a well-grounded estimate rather than a quote.
Can I use it on my phone?
Yes. The page is responsive, weighs a few kilobytes and works offline once loaded, so it behaves the same on a phone as on a desktop.
What people search for
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About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed September 14, 2026 · Calculation runs client-side · No data collected · Report an error