Punnett Square Calculator

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

How the Math Works

The Punnett Square Calculator uses the principles of Mendelian inheritance to predict offspring phenotype ratios from a monohybrid cross. By crossing two parent alleles (e.g., Aa x Aa), the calculator determines all possible allele combinations in offspring. The formula relies on the rule that a recessive trait only manifests when two recessive alleles (aa) are present, while dominant traits (AA or Aa) mask recessive ones. The resulting 3:1 phenotypic ratio (3 dominant : 1 recessive) is derived from the four equally likely genotype combinations (AA, Aa, aA, aa) in the offspring.

Practical Applications

To use this calculator, input the genotypes of the two parent organisms (e.g., Aa for a heterozygous parent). The tool then systematically combines each parent's alleles to generate all possible offspring genotypes. Users can visualize the probability of each phenotype by interpreting the resulting Punnett square. For example, crossing two heterozygous parents (Aa x Aa) yields a 75% chance of dominant traits and 25% recessive traits. This helps researchers, breeders, and educators predict genetic outcomes for traits like flower color, coat patterns, or disease inheritance.

Day-to-Day Use

This calculator simplifies understanding hereditary patterns in everyday scenarios, such as predicting trait likelihood in children (e.g., eye color or genetic disorders) or breeding livestock and plants. Gardeners might use it to anticipate flower colors in seeds, while pet breeders could estimate coat color probabilities. It also empowers individuals to make informed decisions about health risks or family planning by clarifying genetic inheritance probabilities without requiring advanced biology knowledge.

Worked example

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

FAQ