What is a trihybrid cross?

A trihybrid cross involves two parents that differ in three gene loci simultaneously. The Trihybrid Cross Calculator generates all 64 offspring combinations from the 8×8 Punnett square and summarizes genotype and phenotype ratios.

What is the expected phenotype ratio for AaBbCc × AaBbCc?

The Trihybrid Cross Calculator shows that AaBbCc × AaBbCc produces eight phenotype classes in the ratio 27:9:9:9:3:3:3:1, corresponding to all combinations of dominant and recessive expression across the three loci.

How many gamete types does each parent produce in a trihybrid cross?

Each parent can produce 2³ = 8 gamete types (e.g. ABC, ABc, AbC, Abc, aBC, aBc, abC, abc for AaBbCc). The Trihybrid Cross Calculator automatically generates all gametes and builds the 8×8 table.

How do I enter genotypes in the Trihybrid Cross Calculator?

Enter a 6-letter genotype such as AaBbCc, AABBCC, or aabbcc. Each pair of letters must represent the same gene locus. Uppercase = dominant allele, lowercase = recessive allele.

No. All calculations happen in your browser; nothing is sent to a server.

Trihybrid Cross Calculator

How to Use Trihybrid Cross Calculator

The Trihybrid Cross Calculator automates three-gene Mendelian cross analysis with a full 8×8 Punnett square.

Parent 1 Genotype — Enter a 6-letter genotype such as AaBbCc or AABBCC. Each consecutive pair of letters represents one gene locus.
Parent 2 Genotype — Enter the second parent's genotype in the same format (e.g. AaBbCc, aabbcc).
Results — The Trihybrid Cross Calculator instantly shows the 8×8 Punnett square, phenotype ratio table, and all genotype frequencies across 64 offspring slots.

Uppercase letters represent dominant alleles; lowercase letters represent recessive alleles. The Trihybrid Cross Calculator validates your input and highlights invalid genotypes before computation.

Formula & Theory — Trihybrid Cross Calculator

The Trihybrid Cross Calculator extends Mendel's Law of Independent Assortment to three loci. When all three gene loci segregate independently:

Gamete generation (example: AaBbCc):

Each heterozygous parent produces 2³ = 8 gamete types:

ABC, ABc, AbC, Abc, aBC, aBc, abC, abc

Each gamete type has probability 1/8 when all three loci are heterozygous.

Offspring combinations:

The 8×8 Punnett square contains 64 total offspring slots. For the classic AaBbCc × AaBbCc cross, the Trihybrid Cross Calculator yields:

Phenotype ratio  27 : 9 : 9 : 9 : 3 : 3 : 3 : 1

Phenotype class	Count / 64	Probability
A_B_C_	27	42.19 %
A_B_cc	9	14.06 %
A_bbC_	9	14.06 %
aaB_C_	9	14.06 %
A_bbcc	3	4.69 %
aaB_cc	3	4.69 %
aabbC_	3	4.69 %
aabbcc	1	1.56 %

Assumptions

The Trihybrid Cross Calculator assumes complete dominance at each locus and independent assortment among all three loci. Linkage, epistasis, incomplete dominance, and codominance are not modeled.

Use Cases for Trihybrid Cross Calculator

The Trihybrid Cross Calculator is an essential tool for advanced genetics study:

Advanced genetics problems — Solve three-gene cross questions that would take hours to work out by hand, using the Trihybrid Cross Calculator in seconds.
Exam preparation — Practice predicting 27:9:9:9:3:3:3:1 ratios and other trihybrid phenotype distributions with different parental genotypes.
Cross-verification — Verify trihybrid cross results from textbooks or problem sets against the Trihybrid Cross Calculator.
Teaching advanced Mendelian genetics — Demonstrate how independent assortment at three loci multiplies combinatorial complexity to 64 offspring slots.
Probability calculations — Quickly find the probability of any specific genotype or phenotype combination in the offspring of a trihybrid cross.

The Trihybrid Cross Calculator is ideal for AP Biology, college-level genetics, and anyone tackling complex three-trait inheritance problems without building an 8×8 table by hand.