How to use the punnett square calculator
Find offspring genotype and phenotype ratios for a single-gene cross. Enter parent 1, parent 2 in the fields above; the dominant allele chance parent 1, dominant allele chance parent 2, aa offspring, aa offspring, aa offspring, dominant phenotype are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- p1 — Parent 1 (—)
- p2 — Parent 2 (—)
Worked example
With parent 1 = Heterozygous (Aa), parent 2 = Heterozygous (Aa), the calculator gives dominant allele chance parent 1 ≈ 0.5; dominant allele chance parent 2 ≈ 0.5; aa offspring ≈ 25 %; aa offspring ≈ 50 %; aa offspring ≈ 25 %; dominant phenotype ≈ 75 %.
Frequently asked questions
What is the formula for the punnett square calculation?
Dominant allele chance parent 1 = p1===0?1:(p1===1?0.5:0). Dominant allele chance parent 2 = p2===0?1:(p2===1?0.5:0). AA offspring (%) = 100 × [Dominant allele chance parent 1] × [Dominant allele chance parent 2]. Aa offspring (%) = 100 × ([Dominant allele chance parent 1] × (1-[Dominant allele chance parent 2])+(1-[Dominant allele chance parent 1]) × [Dominant allele chance parent 2]). aa offspring (%) = 100 × (1-[Dominant allele chance parent 1]) × (1-[Dominant allele chance parent 2]). Dominant phenotype (%) = 100-[aa offspring]. Here p1 is parent 1 (—), p2 is parent 2 (—).
What inputs do I need for the punnett square calculator (monohybrid) calculator?
You need parent 1 in —, parent 2 in —. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.