Punnett Square Calculator
Cross two parent genotypes for a single trait and get the offspring genotype ratio, phenotype split, and carrier probability.
Dominant phenotype (%)
75
Breakdown
- Recessive phenotype (%)
- 25
- AA offspring (%)
- 25
- Aa offspring (%)
- 50
- aa offspring (%)
- 25
- Carriers (%)
- 50
- Cross
- Aa × Aa
Last updated:
FAQ
What does a Punnett square show?
It lists every combination of parental alleles — one gamete per row and column — so each cell is one equally likely offspring genotype. The classic Aa × Aa cross yields 25% AA, 50% Aa, and 25% aa, which is the familiar 3:1 phenotype ratio.
What is a carrier in genetics?
A heterozygote (Aa) who carries one recessive allele without showing the trait, because the dominant allele masks it. Two carriers have a 25% chance of a child expressing the recessive condition per pregnancy.
Does the square work for blood types?
The principle does, but blood type involves three alleles (IA, IB, i) with co-dominance, so a simple two-allele square is not enough. This calculator covers single-gene, two-allele Mendelian traits.
Related Calculators
Dog Age Calculator
→Convert dog years to human years using breed size and the modern logarithmic formula — far more accurate than ×7.
Cat Age Calculator
→Convert cat years to human years with the AAFP life-stage model — from kitten to senior feline.
Hardy-Weinberg Equilibrium Calculator
→From the recessive phenotype frequency, derive allele frequencies p and q, plus heterozygote (carrier) and homozygous dominant shares of the population.
Bacterial Growth Calculator
→Model exponential microbial growth — enter the starting count, doubling time, and incubation time to project the final population and fold-change.