Punnett Square Calculator

A Punnett square is a genetics chart used to predict the possible genotypes and phenotypes of offspring from a genetic cross. It shows how alleles from each parent can combine through gamete formation and fertilization.

How to Use the Punnett Square Calculator

Select the number of traits in the cross.
Enter the genotype of Parent 1 and Parent 2.
Add trait labels if you want clearer phenotype results.
Click Calculate to see the Punnett square, genotype ratio, phenotype ratio, and explanation.

Monohybrid Cross Calculator

A monohybrid cross follows one trait at a time. Examples include Aa × Aa, Aa × aa, and AA × aa. This is usually the first type of Punnett square students learn.

Dihybrid Cross Calculator

A dihybrid cross follows two traits at the same time, such as AaBb × AaBb. A classic 9:3:3:1 phenotype ratio appears only when both traits show complete dominance and assort independently.

Genotype vs Phenotype

A genotype is the allele combination an organism carries. A phenotype is the observable trait or characteristic produced by that genotype, often in combination with environmental influences. For example, Aa is a genotype, while the expressed dominant trait is the phenotype.

Dominant and Recessive Inheritance

A dominant allele can affect the phenotype when one copy is present. A recessive allele usually affects the phenotype only when two recessive copies are present. Dominant does not mean common, and recessive does not mean weak.

When Punnett Squares Are Most Useful

Punnett squares work best for simple Mendelian inheritance patterns. They are especially useful for learning about alleles, carriers, genotype ratios, phenotype ratios, and how traits can appear or remain hidden across generations.

Not sure if that trait in your family tree follows dominant or recessive inheritance? The Pedigree Analyzer maps it in seconds.

Limits of Punnett Squares

Real inheritance can be more complex than a basic Punnett square. Some traits involve incomplete dominance, codominance, multiple alleles, multiple genes, gene linkage, sex linkage, epistasis, environmental effects, or random developmental variation.

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FAQs

What is a Punnett square calculator?

A Punnett square calculator is an interactive genetics tool that predicts possible offspring genotypes and phenotypes from parent genotypes.

What is a monohybrid cross?

A monohybrid cross follows one trait at a time, such as Aa × Aa. It is often used to teach dominant and recessive inheritance.

What is a dihybrid cross?

A dihybrid cross follows two traits at the same time, such as AaBb × AaBb.

What is the difference between genotype and phenotype?

A genotype is the allele combination an organism carries. A phenotype is the observable trait or characteristic.

Does a Punnett square guarantee the exact offspring outcome?

No. A Punnett square shows probabilities, not guaranteed outcomes for every child or offspring.

Why does the 9:3:3:1 ratio appear in some dihybrid crosses?

The 9:3:3:1 phenotype ratio appears when two traits show complete dominance and assort independently.

Can this calculator model blood type or sex-linked inheritance?

No. This calculator is designed for basic Mendelian crosses. Blood type, sex-linked traits, incomplete dominance, codominance, and polygenic traits need separate models.

Cite this page

BioExplorer. (2026, July 8). Punnett Square Calculator. https://www.bioexplorer.net/punnett-square-calculator/