🌱 Punnett Square Calculator
Visualize allele inheritance and predict offspring ratios for a single gene.
How to Use This Calculator
Enter parental genotypes
Use two-letter genotypes such as AA, Aa, or aa. Uppercase letters represent dominant alleles.
Generate the Punnett square
Click the button to build the grid of possible offspring genotypes.
Interpret ratios
Review genotype counts and percentages to understand inheritance probabilities.
Formula
Punnett outcome = gameteP1 × gameteP2
Each parent contributes one allele to every offspring. Counting the resulting genotypes in the Punnett square yields the probability distribution for the cross.
Full Description
Punnett squares illustrate Mendelian inheritance for a single gene. By aligning parental gametes along the top and side of a grid, each cell captures a potential genotype for the offspring. Summing the outcomes reveals expected ratios such as 3:1 in monohybrid crosses.
This approach assumes independent assortment, equal gamete contribution, and complete dominance for the uppercase allele. Deviations in real-world data may indicate co-dominance, incomplete dominance, or other genetic interactions.
Frequently Asked Questions
Can I include multiple genes in this calculator?
This tool is limited to a single gene (monohybrid) cross. For multi-gene crosses, use the dihybrid or trihybrid calculators.
How do I represent co-dominance?
Use uppercase/lowercase letters for Mendelian dominance. For co-dominant or incomplete dominance, treat results qualitatively and interpret heterozygous genotypes accordingly.
Does genotype order matter when typing it?
No. The calculator normalizes allele order (e.g., aA becomes Aa) so you can enter uppercase or lowercase in any order.
What if a parent produces only one gamete?
Homozygous parents (AA or aa) generate a single allele type. The Punnett square reflects this by duplicating the same gamete across rows or columns.