What is the Punnett Square Calculator?
A Punnett square predicts the possible offspring of two parents by combining every gamete from one with every gamete from the other. Aa × Aa gives the classic 3:1 phenotype ratio; AaBb × AaBb gives 9:3:3:1.
How to use it
- 1
Enter both parents
e.g. AaBb — capital letters are dominant.
- 2
Read the square
Each cell is one possible offspring.
- 3
Check the ratios
Genotype and phenotype breakdowns.
Features
1, 2 or 3 genes
Up to an 8 × 8 trihybrid square.
Gametes shown
Along both edges of the square.
Ratios and percentages
For genotypes and phenotypes.
Presets
Monohybrid, dihybrid and test crosses.
Popular uses
Biology homework
Mendelian genetics problems.
Teaching
Show how ratios arise.
Breeding
Plan simple trait crosses.
Frequently asked questions
Does it handle incomplete dominance?
It assumes complete dominance; for incomplete dominance read the genotype ratio instead.
What about linked genes?
Genes are assumed to sort independently.