equine coat color calculator

How this equine coat color calculator works

This calculator estimates possible foal coat colors by combining parent genotypes at three important loci: Extension, Agouti, and Cream. It runs a simple Mendelian probability model and reports likely phenotype percentages. In plain English, it answers: “Given these parents, what colors are most likely?”

If you know your horse DNA test results, you can plug them in directly. If you are estimating, choose the most likely genotype and compare multiple scenarios.

Quick genetics primer for horse coat colors

1) Extension (E/e)

Extension controls whether black pigment can be produced.

• EE or Ee: black pigment is possible.
• ee: no black pigment; red-based coat (chestnut family).

2) Agouti (A/a)

Agouti only matters when black pigment is present (E_ horses). It controls where black pigment is placed.

• A_: black points with red body = bay patterning.
• aa: unrestricted black pigment = black base.

3) Cream (Cr)

Cream is a dilution gene with dosage effects.

• NN: no cream dilution.
• NCr: single cream dilution (palomino, buckskin, smoky black).
• CrCr: double cream dilution (cremello, perlino, smoky cream).

Color outcomes modeled in this tool

The calculator maps genotype combinations into these common phenotype groups:

• Chestnut, Bay, Black
• Palomino, Buckskin, Smoky Black
• Cremello, Perlino, Smoky Cream

How to use the calculator effectively

1. Select sire and dam genotype at each locus.
2. Click Calculate Foal Colors.
3. Read the probability table, not just the top result.
4. Re-run with alternative genotypes if parent status is uncertain.

Example breeding scenario

Suppose a buckskin parent is likely Ee Aa NCr, and the other parent has no cream and is Ee Aa NN. You should see a mix of bay/chestnut/black families with a subset diluted by cream. The exact percentages depend on each locus independently and then combine into final phenotypes.

Important limitations

Real horse color genetics can be more complex. This model is intentionally focused so it stays fast and easy to use.

• It does not model Gray (G), Dun (D), Champagne, Silver, Pearl, Mushroom, or Roan.
• It does not model white pattern genes (Tobiano, Frame Overo, Splash, Sabino, etc.).
• It does not account for registration naming differences between breed registries.

For critical breeding decisions, pair this with laboratory DNA testing and a qualified equine genetics specialist.

Why probability matters

Even when both parents are known, foal color is never guaranteed unless genetics forces one outcome. Breeding is probabilistic. Over many foals, percentages tend to match predictions. For a single foal, the result can still surprise you.