🧬 Punnett Square Calculator
Predict genetic outcomes! Select a trait, enter the parents' genotypes, and instantly calculate the probability of the offspring's physical traits.
Select Trait:
Parent 1 (Top):
Parent 2 (Left):
Parent 1 Alleles
Parent 2 Alleles
B
b
B
b
BBBrown
BbBrown
BbBrown
bbBlue
Dominant Phenotype (Brown)
75%
Recessive Phenotype (Blue)
25%
🔬 Mendelian Genetics 101
A Punnett square is a diagram used by biologists to predict the outcome of a particular cross or breeding experiment.
- Alleles: Letters represent genes. A capital letter (e.g., B) is a Dominant trait. A lowercase letter (e.g., b) is a Recessive trait.
- Genotype: The genetic makeup (the letters). Homozygous means two of the same (BB or bb). Heterozygous means mixed (Bb).
- Phenotype: The physical appearance (what you actually see). If a dominant allele is present, it "overpowers" the recessive one and dictates the physical trait!