Punnett Square Calculator
Calculate genetic cross outcomes, genotype ratios, and phenotype probabilities using a Punnett square.
Parent Alleles
(Heterozygous)
(Heterozygous)
Tip: Use uppercase for dominant alleles (A) and lowercase for recessive alleles (a).
Punnett Square
| A | a | |
|---|---|---|
| A | AA | aA |
| a | aA | aa |
Phenotype Ratio
3
Dominant
75%
1
Recessive
25%
3 : 1
Genotype Ratios
AA
25%(1/4)
Aa
50%(2/4)
aa
25%(1/4)
About Punnett Squares
A Punnett square is a diagram used to predict the genotypes of offspring from a genetic cross.
Homozygous: Two identical alleles (AA or aa)
Heterozygous: Two different alleles (Aa)
Dominant: Expressed when at least one copy is present
Recessive: Only expressed when homozygous
💡
Help us improve!
How would you rate the Punnett Square Calculator?
Editorial Note
MyCalcBuddy Editorial Team
This page is maintained as an educational calculator reference.
📚
Formula Source: Standard Mathematical References
by Various
🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.