What This Calculator Does
This calculator predicts the expected phenotype breakdown for a classic trihybrid cross, where an individual heterozygous for three independent genes (AaBbCc) is crossed with another individual of the same genotype (AaBbCc × AaBbCc).
The Method
For three independently assorting gene pairs, each with simple dominant/recessive inheritance, the resulting 64-square Punnett square produces phenotypes in the classic 27:9:9:9:3:3:3:1 ratio. This calculator scales that standard ratio to whatever total number of offspring you enter, giving the expected count for each of the 8 phenotype combinations.
- Enter the total number of offspring you want to predict counts for (64 shows the ratio in its simplest whole-number form).
- Results are theoretical expectations; actual litters or broods will vary due to random chance, especially with small sample sizes.
This tool assumes standard Mendelian inheritance (complete dominance, independent assortment) and is intended for general genetics education.
Last reviewed August 2026