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Dihybrid Cross Calculator.

Enumerate two-locus offspring genotype probabilities from explicit parent genotypes.

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01

Set your values

Results update as you type.

Punnett cells: 16

Punnett cells

16.00

Offspring genotype probabilities

aabb6.25%
aaBb12.50%
aaBB6.25%
Aabb12.50%
AaBb25.00%
AaBB12.50%
AAbb6.25%
AABb12.50%
AABB6.25%

How to Use

Each parent is two adjacent loci (for example AaBb). The four-by-four cross enumerates genotype probabilities only; no dominance or phenotype interpretation is applied.

Use measured values and a documented convention. This calculator does not provide medical, veterinary, phenotype, or laboratory-method advice.

Use Cases

Predict offspring genotype ratios

Use this calculator to determine the probability of each genotype in the offspring when both parents are known for two traits. This is helpful for genetics students and breeders.

Example: Cross AaBb x AaBb to see the classic 1:2:1 ratio for each gene and the combined 9:3:3:1 phenotypic ratio.

Verify genetic crosses

Check your manual Punnett square calculations for two-locus crosses. This tool provides a quick reference to confirm genotype probabilities.

Example: Enter AaBb x aabb to see the expected 1:1:1:1 genotype ratio.

Frequently Asked Questions

What is a dihybrid cross?
A dihybrid cross is a breeding experiment between two organisms that are identically heterozygous for two traits. It examines the inheritance of two different genes simultaneously, typically resulting in a 9:3:3:1 phenotypic ratio in the offspring if the genes are unlinked.
How do I use the Dihybrid Cross Calculator?
Enter the genotypes of both parents for two loci (e.g., AaBb). The calculator will enumerate all possible gamete combinations and display the genotype probabilities for the offspring. Simply input the alleles for each gene for both parents.
What does 'explicit parent genotypes' mean?
It means you provide the exact allele pairs for each parent at both loci, such as AaBb. The calculator uses these to determine all possible gametes and then combines them to show the distribution of offspring genotypes.

Tips & Common Mistakes

Tips

  • Ensure you enter the alleles in the correct order for each locus (e.g., A then a for heterozygous).
  • Double-check that both parents have two alleles for each gene; missing alleles may lead to incorrect results.
  • Use this calculator for educational purposes to understand Mendelian inheritance patterns.
  • Remember that this tool assumes independent assortment; linked genes may not follow these probabilities.

Common Mistakes to Avoid

  • Entering only one allele per locus instead of two (e.g., 'A' instead of 'AA' or 'Aa').
  • Confusing the order of loci: make sure the first locus alleles are consistent across both parents.
  • Assuming the calculator accounts for linkage or sex-linked traits; it only handles independent assortment.

Last updated: August 13, 2026