Coat Color Calculator

Use this coat color calculator to estimate likely offspring coat colors from sire and dam genotypes. Compare phenotype percentages and genotype outcomes for dogs, horses, cats, and cattle.

Predicting Offspring Coat Color Probabilities

This tool predicts possible offspring coat color outcomes from sire and dam genotypes. It clearly shows the phenotype probability and the resulting genotype distribution for a specific pairing.

This is a 2-locus genetics calculator. The supported models are the dog (B and E loci), horse (E and A loci), cat (B and D loci), and cattle (E and D loci). The results apply only to the included loci in the selected model, not full real-world coat genetics.

Formula

Each parent has two selected loci, and each locus contributes one allele per gamete. The calculator creates four gametes from the sire and four gametes from the dam. Those are crossed into 16 total offspring combinations. Each combination is classified into a phenotype result and a genotype result. Percentages are calculated from the number of matching outcomes out of 16.

$$\text{Outcome Probability (\%)} = \frac{\text{Number of matching offspring combinations}}{16} \times 100$$

Formula part	Meaning in this calculator
2 loci per parent	The tool models two genes only
4 sire gametes	All allele combinations the sire can pass
4 dam gametes	All allele combinations the dam can pass
16 total outcomes	All modeled offspring genotype combinations
Percentage output	Matching outcomes ÷ 16 × 100

Note: Genotypes are displayed locus-by-locus, for example Bb · Ee.

How the Coat Color Calculator Works

This calculator uses parent genotypes to simulate all possible two-locus offspring outcomes for the selected species model.

Step	What you do	What the calculator does
1	Select the animal species / genetics model	Loads the correct loci and phenotype rules
2	Select sire gene 1 and sire gene 2	Defines the sire genotype
3	Select dam gene 1 and dam gene 2	Defines the dam genotype
4	View predicted phenotype results	Groups visible coat outcomes by percentage
5	View genotype distribution	Shows how often each genotype appears

Calculator Inputs

The calculator uses one species selector and four genotype inputs. Changing the species changes the available loci and the phenotype rules used in the result.

Input	What it means	Effect on calculation
Animal species / genetics	Dog, horse, cat, or cattle model	Loads species-specific loci and phenotype rules
Sire gene 1	First sire locus	Used to generate sire gametes
Sire gene 2	Second sire locus	Used to generate sire gametes
Dam gene 1	First dam locus	Used to generate dam gametes
Dam gene 2	Second dam locus	Used to generate dam gametes

Note: The calculator does not run until all four parent loci are selected.

Supported Species, Loci, and Coat Color Outputs

Species	Included loci	What the tool predicts
Dog	B locus + E locus	Black, Chocolate / Brown, Yellow / Red
Horse	E locus + A locus	Chestnut, Bay, Black
Cat	B locus + D locus	Black, Chocolate, Blue (Grey), Lilac
Cattle	E locus + D locus	Black, Red, Black Dun (Grullo), Red Dun

Phenotype Rules Used by This Coat Color Calculator

The calculator converts each offspring genotype into a coat color category using the following species-specific rules.

Species	Rule applied by the calculator	Predicted phenotype
Dog	ee at E locus	Yellow / Red Coat
Dog	E present and B present	Black Coat
Dog	E present and bb	Chocolate / Brown Coat
Horse	ee at E locus	Chestnut Coat
Horse	E present and A present	Bay Coat
Horse	E present and aa	Black Coat
Cat	B present and not dd	Black Coat
Cat	bb and not dd	Chocolate Coat
Cat	B present and dd	Blue (Grey) Coat
Cat	bb and dd	Lilac Coat
Cattle	E present and dd	Black Coat
Cattle	ee and dd	Red Coat
Cattle	E present and D present	Black Dun (Grullo)
Cattle	ee and D present	Red Dun Coat

Understanding the Results

Phenotype percentages show the share of the 16 modeled outcomes that produce each visible coat category.

Genotype distribution shows how often each allele combination appears across the same 16 modeled offspring results.

Result type	What it shows	How to read it
Phenotype probability	Visible coat color outcome	A higher percentage means that phenotype appears more often in the modeled 16 outcomes
Genotype distribution	Specific allele combination	A higher percentage means that genotype appears more often in the modeled cross

If a phenotype shows 50%, that means 8 of 16 modeled offspring outcomes fall into that coat color category.

Example Cross

Parent	Locus 1	Locus 2
Sire	Bb	Ee
Dam	Bb	ee

The calculator generates sire and dam gametes. It crosses them into 16 possible offspring combinations. It groups those combinations into predicted phenotype and genotype percentages. For instance, this specific dog cross results in a 50% probability of a yellow/red coat, which means 8 of the 16 modeled combinations produce that color.

What to check	Why it matters
Phenotype percentages	Shows which coat colors are possible and how likely they are
Genotype distribution	Shows which allele combinations produce those results

Included Loci and Omitted Genetics

This tool is intentionally limited to two loci per species. Real coat color inheritance can involve additional genes, modifiers, and breed-specific patterns.

Species	Included in this calculator	Important genetics not included
Dog	B, E	K, A, D, S, M and other breed-specific modifiers
Horse	E, A	Gray, Cream, Dun, Roan, Champagne, Pearl, Silver, Tobiano, Sabino and other pattern genes
Cat	B, D	Orange, Agouti, Tabby, Dominant White, White Spotting, Silver
Cattle	E, D	Breed-specific variation, Roan, Color-Sided, white spotting, and other modifiers

Best Use Cases for This Coat Color Calculator

This calculator is most useful for comparing likely offspring coat outcomes from two known parent genotypes, checking simplified genotype-to-phenotype probabilities, learning basic 2-locus inheritance with animal-specific examples, and getting a quick probability estimate before deeper species-specific analysis.

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