Punnett Square Calculator

Visualize Genetic Crosses & Probabilities

Enter the genotypes of two parents to generate a Punnett square and calculate the probability of each possible offspring genotype and phenotype.

Examples

Try these sample genetic crosses:

Heterozygous x Heterozygous (Aa x Aa)

Monohybrid

Classic Mendelian cross for a single trait.

Parent 1 Genotype: Aa

Parent 2 Genotype: Aa

Dominant Allele: A

Recessive Allele: a

Trait Name: Seed Shape

Homozygous Dominant x Homozygous Recessive (AA x aa)

Monohybrid

All offspring will be heterozygous.

Parent 1 Genotype: AA

Parent 2 Genotype: aa

Dominant Allele: A

Recessive Allele: a

Trait Name: Flower Color

Heterozygous x Homozygous Recessive (Aa x aa)

Monohybrid

50% heterozygous, 50% homozygous recessive offspring.

Parent 1 Genotype: Aa

Parent 2 Genotype: aa

Dominant Allele: A

Recessive Allele: a

Trait Name: Eye Color

Homozygous Dominant x Heterozygous (AA x Aa)

Monohybrid

50% homozygous dominant, 50% heterozygous offspring.

Parent 1 Genotype: AA

Parent 2 Genotype: Aa

Dominant Allele: A

Recessive Allele: a

Trait Name: Hair Texture

Other Titles
Understanding the Punnett Square Calculator: A Comprehensive Guide
Master genetic cross predictions and inheritance patterns.

What is a Punnett Square?

  • Definition and History
  • Purpose in Genetics
  • Visualizing Inheritance
A Punnett square is a diagram used in genetics to predict the possible genotypes of offspring from a particular cross or breeding experiment. Developed by Reginald C. Punnett, it is a foundational tool in Mendelian genetics.
Why Use a Punnett Square?
It helps visualize how alleles from each parent combine and the probability of each genotype and phenotype in the offspring.

Common Use Cases

  • Predicting pea plant flower color
  • Determining carrier status for genetic diseases

Step-by-Step Guide to Using the Calculator

  • Inputting Parent Genotypes
  • Setting Allele Letters
  • Interpreting Results
How to Use the Calculator
Enter the genotypes of both parents, specify which allele is dominant and which is recessive, and optionally name the trait. The calculator will generate the Punnett square and show genotype and phenotype probabilities.

Step-by-Step Examples

  • Aa x Aa cross for seed shape
  • AA x aa cross for flower color

Real-World Applications of Punnett Squares

  • Education and Teaching
  • Genetic Counseling
  • Research and Breeding
Punnett squares are widely used in classrooms to teach inheritance, in genetic counseling to assess risk, and in research to predict breeding outcomes.
Beyond the Classroom

Applications

  • Predicting risk of inherited diseases
  • Planning plant or animal breeding programs

Common Misconceptions and Correct Methods

  • Misreading Genotypes
  • Assuming Equal Probability
  • Ignoring Multiple Traits
Avoiding Mistakes
It's important to enter genotypes correctly and understand that Punnett squares show probabilities, not certainties. For multiple traits, more complex squares are needed.

Misconceptions

  • Confusing Aa with AA
  • Assuming all outcomes are equally likely

Mathematical Derivation and Examples

  • Genotype Combinations
  • Probability Calculations
  • Sample Crosses
The Punnett square is based on the principle of independent assortment. Each parent's alleles are split and combined to form all possible offspring genotypes. Probabilities are calculated by dividing the count of each genotype by the total number of combinations.
Worked Example
For Aa x Aa: Possible gametes are A and a from each parent. The square yields AA, Aa, aA, and aa. Grouping Aa and aA gives 1 AA : 2 Aa : 1 aa ratio.

Mathematical Examples

  • Calculating 3:1 phenotype ratio
  • Finding carrier probability in a family