Punnett Square Calculator

Calculate genetic traits with our free Punnett Square Generator. Create monohybrid and dihybrid crosses for biology class instantly.

Genetic Cross Configuration

Parent 1 Genotype

Mother alleles

Parent 2 Genotype

Father alleles

Mastering Genetics

The Punnett square is a visual representation of Mendelian inheritance. It allows biologists to predict the probability of an offspring having a particular genotype. Whether you are studying simple dominance, incomplete dominance, or dihybrid crosses, this tool simplifies the combination process.

Monohybrid

Single trait cross (e.g. Flower Color). Results in a 2x2 grid.

Dihybrid

Two trait cross (e.g. Color & Height). Results in a 4x4 grid.

Inheritance

Visualize dominant vs recessive allele transmission.

Visualize Genetic Inheritance with a Punnett Square

Enter the genotypes of two parents — using standard allele notation like Aa or AaBb — and this tool builds the complete Punnett square grid. It calculates the probability of each offspring genotype and groups them into phenotypic ratios, showing the classic dominant-to-recessive outcomes for both monohybrid and dihybrid crosses. Ideal for biology students, educators, and anyone studying Mendelian genetics.

Monohybrid & dihybrid crosses

Why Use This Tool?

Visual grid layout

The tool renders a proper Punnett square table showing every gamete combination so you can follow each cross the way it is taught in class.

Genotype & phenotype ratios

Results include both genotype ratios (e.g., 1 AA : 2 Aa : 1 aa) and phenotype ratios (3 dominant : 1 recessive) with percentage breakdowns.

Supports dihybrid crosses

Enter four-allele genotypes like AaBb to generate a 4×4 Punnett square covering all 16 offspring combinations for two independent traits.

Instant recalculation

Results update as you type or click Calculate, making it easy to experiment with different parental genotypes and compare outcomes quickly.

How this Punnett Square Calculator works

Our Punnett Square Generator creates genetic cross diagrams from the parental genotypes you provide. Enter the alleles for each parent, and the tool constructs the complete Punnett square grid showing all possible offspring genotypes along with their phenotypic ratios and probability percentages.

All calculations are performed in your browser using JavaScript. No genetic data or inputs are sent to any server, ensuring your academic work and research queries remain private. The tool applies Mendelian inheritance rules to accurately compute genotype and phenotype distributions for monohybrid and dihybrid crosses.

The generator supports single-trait and two-trait crosses, displays dominant and recessive phenotype predictions, and calculates exact offspring ratios. It produces clean, printable diagrams suitable for biology homework, classroom demonstrations, genetics coursework, and breeding program planning. Color-coded output helps distinguish between homozygous and heterozygous genotypes at a glance.

How to use this Punnett Square Calculator

Enter Genotypes

Input mother and father alleles (e.g., Aa for one trait, AaBb for two).

Calculate

Generate the Punnett Square grid automatically.

Analyze

View genotype probabilities and ratios instantly.

Example Usage

Classic Mendelian monohybrid cross.

Input

Parent 1: Aa, Parent 2: Aa

Output

25% AA, 50% Aa, 25% aa

Frequently Asked Questions

What is a Punnett Square?

A diagram used to predict the genotypes of a particular cross or breeding experiment. It is named after Reginald C. Punnett.

How do I format the input?

Use letters to represent alleles. Capital for dominant (A), lowercase for recessive (a). For two traits, combine them (e.g., AaBb).

Does order matter?

Standard convention is to keep same-letter alleles together (e.g., Aa, not aA) and dominant alleles first. Our tool handles the sorting for you.

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The Punnett Square Calculator is maintained by CodeItBro. We aim to provide the best free developer tools on the web. If you have feedback or suggestions, please visit our contact page.

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