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Monohybrid Cross 3:1 Calculator

Expected counts for a heterozygous-by-heterozygous monohybrid cross.

Compute the expected offspring counts in each phenotypic class (3:1 dominant:recessive) for a monohybrid cross between two heterozygotes (e.g. Rr × Rr).

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

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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

Expected: 3/4 dominant phenotype, 1/4 recessive. Genotype: 1 RR : 2 Rr : 1 rr.

In depth

Compute the expected offspring counts in each phenotypic class (3:1 dominant:recessive) for a monohybrid cross between two heterozygotes (e.g. Rr × Rr).