Horse Coat Color Calculator

Coat color in horses is determined by genes passed from both the sire and the dam. The two base genes — Extension (E) and Agouti (A) — control whether a horse is black, bay, or chestnut. Modifiers like cream, dun, gray, roan, and tobiano then act on that base color. This calculator estimates the most likely foal colors based on those inheritance patterns. For exact genetic status of either parent, DNA testing from a laboratory is the most accurate method.

The outcome depends on both parents' genotypes. A black horse can carry the recessive chestnut allele (e). If the black parent is EE, none of the foals will have a chestnut base color. If it is Ee and the chestnut parent is ee, each foal has a 50 percent chance of a chestnut base. Bay is possible if the chestnut parent passes on Agouti (A), which can be hidden by its chestnut coat. A black base requires aa. Use Advanced mode to enter tested genotypes for a more precise breakdown.

Yes. Gray is caused by a dominant modifier gene (G) that progressively removes pigment from the coat over time. A foal born to at least one gray parent has a 50 percent or higher chance of turning gray, even if it is born a solid color. The graying process typically begins within the first year and continues throughout the horse's life. A horse with two copies of the gray gene (GG) will always pass gray to its foals. Gray horses are often born dark and lighten gradually — the final coat color is not visible at birth.

Yes. Classic roan and dun are inherited as dominant traits, so one copy from either parent can produce the trait. A heterozygous roan (Rnrn) or dun (Dd) parent passes the relevant allele to each foal with a 50 percent probability. Homozygous classic roan horses are viable; RnRn is not lethal. Dun lightens the body and produces primitive markings, such as a dorsal stripe and leg barring. Use Advanced mode if a parent has two copies.

Not always. Palomino and buckskin horses each carry one copy of the cream gene (Crn). When crossed with a non-dilute horse, approximately half the foals will inherit the cream allele. The resulting color depends on the base: palomino, buckskin, or smoky black. Two single-cream parents give each foal a 25 percent chance of inheriting two cream copies, producing cremello, perlino, or smoky cream according to its base. Palomino crossed with palomino can produce chestnut, palomino, or cremello foals.

Coat color changes in foals can be caused by the gray gene, which progressively removes pigment from the coat, often beginning within the first year. A foal that appears bay or chestnut at birth may show white hairs around the eyes and muzzle within months. Roan may become clearer after the first shedding. Foals also naturally shed their birth coat for an adult coat that can look different; this alone does not mean they carry gray.

Dilute coat colors occur when a dilution variant lightens the base color. One cream copy (Cr) changes chestnut to palomino, bay to buckskin, and black to smoky black, which may still look black. Two copies produce cremello, perlino, or smoky cream, respectively. These double dilutes have pale cream coats and blue eyes. Dun is a separate dilution that lightens the body and produces a dorsal stripe and other primitive markings.

No. This calculator is a learning and planning tool based on common inheritance patterns. Visible coat color does not reveal every allele a horse carries. Simple mode assumes genotypes; Advanced mode uses the ones you enter. Laboratory DNA testing is needed to identify specific variants, including cream, silver, and frame overo, or inherited conditions such as HYPP. Tests identify the variants included in the panel; they do not detect every possible genetic cause.

Horse color genetics is a deep subject that goes well beyond the basic color names. Understanding Extension, Agouti, cream, dun, silver, and pattern genes gives you a much clearer picture of what to expect from any breeding. Horse Education Online offers structured study materials, certification programs, and reference books that cover equine genetics as part of broader equine science education.