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.

A black horse crossed with a chestnut depends on the exact genotypes of each parent. Black is dominant over chestnut, but a black horse can carry a hidden recessive red (chestnut) gene. If the black parent is homozygous (EE), all foals will be black or bay. If heterozygous (Ee), roughly half could be chestnut. Bay foals are also possible if the black parent carries the Agouti gene. Use the Advanced mode in this calculator to enter specific 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. Both roan and dun are caused by dominant modifier genes, meaning only one copy from one parent is needed to produce the trait in a foal. A roan parent (Rnrn) passes the roan gene to approximately half its foals. Dun (Dd) works the same way. Homozygous roan (RnRn) is considered non-viable, so all living roan horses carry only one copy. Dun adds primitive markings — a dorsal stripe, leg barring, and shoulder striping — to whatever base color the foal inherits.

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 gene and be dilute (palomino or buckskin), and half will not. When two single-dilute horses are crossed, roughly one in four foals will inherit two cream copies and become double-dilute (cremello or perlino). The exact outcome depends on the base color of each parent — palomino crossed with palomino can produce chestnut, palomino, or cremello foals.

Coat color changes in foals are most commonly caused by the gray gene, which progressively removes pigment from the coat starting within the first year of life. A foal that appears bay or chestnut at birth may begin to show white or silver hairs around the eyes and muzzle within months. Roan foals may also appear darker at birth and lighten slightly with their first adult coat. Some foals simply shed their birth coat for a different adult color — this is normal and not related to the gray gene.

Dilute coat colors occur when one or more copies of a dilution gene lighten the base color. The most common dilution gene in horses is cream (Cr). One copy lightens chestnut to palomino, bay to buckskin, and black to smoky black. Two copies produce strong double dilutes: cremello (from chestnut base), perlino (from bay base), or smoky cream (from black base). Double dilutes have pale cream coats and blue eyes. Dun is a separate dilution gene that produces a dorsal stripe and primitive markings along with a lightened body color.

No. This calculator is a learning and planning tool based on common inheritance patterns. It works well for estimating probable foal colors when you know the visible traits of the parents. However, it cannot detect hidden genes — a horse can carry a recessive gene without showing it. For breeding decisions where exact genotype matters, particularly for cream, silver, frame overo, or HYPP, laboratory DNA testing provides a definitive result. Many breed registries now offer or require color and trait panels for registration.

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.