Punnett Square Calculator

Find offspring phenotype ratios from a monohybrid cross.

Parent 1 genotype

Parent 2 genotype

Dominant phenotype (%) 75

Recessive phenotype (%) 25

Formula: cross the alleles; recessive needs two recessive alleles

Step-by-step with your numbers:

1. Values used:

3. Dominant phenotype = 75%

4. Recessive phenotype = 25%

Did we solve your problem today?

Predict the offspring of a single-gene (monohybrid) cross.

The math behind it

Each parent passes one of its two alleles. The recessive phenotype only appears when both inherited alleles are recessive.

Aa × Aa → 75% dominant, 25% recessive (the classic 3:1).

Two genes?

Use the dihybrid cross calculator.