Punnett Square Calculator
Cross two parents and get genotype and phenotype ratios, for one trait or two.
Genotype ratio
Phenotype ratio
Simulated offspring
Squares in grid4
Unique genotypes0
Unique phenotypes0
What you can learn
- Each parent passes one allele of each gene to the offspring, chosen at random.
- A monohybrid cross Aa × Aa gives a 3:1 phenotype ratio.
- A dihybrid cross AaBb × AaBb gives the classic 9:3:3:1 ratio.
Frequently asked questions
What is the difference between genotype and phenotype?
Genotype is the pair of alleles an organism carries, such as Rr. Phenotype is the visible trait, such as round seeds.
What is a dihybrid cross?
A cross that follows two genes at once. Each parent makes four kinds of gametes, so the Punnett square is 4 by 4.