Equine Color Calculator

Predict your foal’s coat colors and patterns from the sire’s and dam’s genetic test results.

Sire's Genetics

Extension (Red/Black Factor)

Agouti

Restricts black pigment to the points (mane, tail, legs). Only affects black-based horses.

Cream

A dilution gene that lightens the coat, with a stronger effect when homozygous.

Dun

A dilution gene that lightens the body and adds primitive markings.

Silver

Dilutes black pigment on the body and mane/tail. Does not affect red pigment.

Champagne

A dominant dilution gene that lightens both red and black pigment, often with mottled skin.

Gray

Causes progressive graying with age, eventually turning the horse white. Masks all other colors.

Roan

Causes white hairs to be intermixed with the base coat color on the body.

Tobiano

A dominant pinto pattern characterized by large, rounded white patches.

Frame Overo (LWO)

A pinto pattern. Homozygous (OO) results in Lethal White Overo syndrome.

Dam's Genetics

Extension (Red/Black Factor)

Agouti

Restricts black pigment to the points (mane, tail, legs). Only affects black-based horses.

Cream

A dilution gene that lightens the coat, with a stronger effect when homozygous.

Dun

A dilution gene that lightens the body and adds primitive markings.

Silver

Dilutes black pigment on the body and mane/tail. Does not affect red pigment.

Champagne

A dominant dilution gene that lightens both red and black pigment, often with mottled skin.

Gray

Causes progressive graying with age, eventually turning the horse white. Masks all other colors.

Roan

Causes white hairs to be intermixed with the base coat color on the body.

Tobiano

A dominant pinto pattern characterized by large, rounded white patches.

Frame Overo (LWO)

A pinto pattern. Homozygous (OO) results in Lethal White Overo syndrome.

How the Equine Color Calculator Works

The Equine Color Calculator uses each parent’s genetic test results to estimate the possible coat colors and patterns of their foal. By combining the sire’s and dam’s genotypes for key color genes, it builds all potential foal genotypes and assigns a probability to each one.

1. Enter Parent Genotypes

Select the sire’s and dam’s results for genes like Extension (black/red), Agouti (bay/black), Cream, Dun, Silver, Champagne, Gray, Roan, Tobiano, and Frame Overo. These values usually come directly from a laboratory genetic test.

2. Create Punnett Squares

For each gene, the calculator builds a Punnett square using the alleles from each parent (for example, Ee × Ee ). All possible foal genotypes for that gene (such as EE, Ee, ee ) are generated, and each combination is given a probability (typically in 25% increments).

3. Combine All Genes

The tool then “stacks” the single–gene Punnett squares together, creating every possible full foal genotype (all genes at once). The probability for each full genotype is calculated by multiplying the individual gene probabilities.

4. Translate Genotype to Coat Color

For each possible genotype, a set of rules is applied: base color is determined first (black, bay, or chestnut), then dilutions (cream, dun, champagne, silver) modify that base, and finally white patterns (gray, roan, tobiano, frame overo) are layered on top. Lethal combinations, such as double frame overo ( OO ), are flagged as non-viable rather than assigned a coat color.

The results are then grouped by final coat color and pattern, and their probabilities are summed and displayed so you can see which foal colors are most and least likely from your specific pairing.

Frequently Asked Questions

Where is the color Brown?

In horses, “brown” usually means seal brown (At)—a very dark form of bay. In the calculator, choose Base: Bay and (if offered) Shade/Subtype: Seal Brown (At). If no subtype option exists, select Bay.

How do I select Gray for my Sire or Dam?

Gray is a dominant modifier (G), separate from the base color. In the parent panel: Pick the horse's base color (Bay, Black, Chestnut, etc.) Toggle Gray (G) on. Notes: GG = all foals gray, Gg ≈ 50% gray on average.

Where is Chocolate?

Bu“Chocolate” in horses typically refers to the Silver (Z) dilution on a black-based coat (often called silver dapple). In the calculator, select Base: Black (or Bay), then add Silver (Z). Black + Silver (Z) → classic “Chocolate/Silver Dapple” look Bay + Silver (Z) → “Silver Bay” Chestnut + Silver (Z) → no visible change (carrier only)

Where is Taffy?

“Taffy” is a regional term (common in AUS/NZ) for Silver (Z)-diluted coats. Use Silver (Z) with the correct base: Black + Silver (Z) → Chocolate Taffy Bay + Silver (Z) → Bay Taffy Chestnut + Silver (Z) → looks chestnut (carrier), still select Silver (Z) if you want genetics shown.