🟩Punnett Square Calculator

Enter both parents' genotypes to build a monohybrid or dihybrid Punnett square, with genotype and phenotype ratios shown.

Parent 1 genotype

Parent 2 genotype

Gene 1 — dominant trait name

Gene 1 — recessive trait name

Free Punnett Square Calculator

Working through genetics and need a quick cross? Our free Punnett Square Calculator builds the full grid for you. Enter both parents' genotypes for a monohybrid cross (one gene) or a dihybrid cross (two genes), name the traits if you like, and get the complete offspring grid instantly — no manual gamete-pairing required.

Beyond the grid, you get the genotype ratio (like 1 AA : 2 Aa : 1 aa) and the phenotype ratio with percentages, using standard complete-dominance rules and your own trait labels. It handles both 2×2 monohybrid crosses and 4×4 dihybrid crosses, generating every possible gamete combination automatically so nothing gets missed.

Perfect for checking genetics homework, studying for a biology exam, or just refreshing how Mendelian inheritance works. No sign-up, no downloads — enter your genotypes and see the results immediately. See the About page or the FAQ for more.