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Punnett Square Calculator

Build a Punnett square for a single-gene cross and get the expected genotype and phenotype ratios.

Daniel Oh By Daniel Oh
Reviewed by Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Cross each parent's possible gametes in a 2×2 grid; genotype ratio comes from counting cells, phenotype ratio from dominance rules.

In depth

Build a Punnett square for a single-gene cross and get the expected genotype and phenotype ratios.