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Test Cross Probability Calculator

Probability of recessive offspring given parent genotypes.

Compute the probability that a single offspring shows the recessive phenotype for a single autosomal gene, given the genotypes of two parents (homozygous dominant, heterozygous, or homozygous recessive).

Priya Venkatesan By Priya Venkatesan
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

P(recessive offspring) = P(parent1 contributes recessive allele) × P(parent2 contributes recessive allele).

In depth

Compute the probability that a single offspring shows the recessive phenotype for a single autosomal gene, given the genotypes of two parents (homozygous dominant, heterozygous, or homozygous recessive).