Foal Coat Color Calculator
Use this horse color calculator to estimate possible foal coat colors from three major loci: Extension (E/e), Agouti (A/a), and Cream (Cr/n).
Sire (Stallion)
Dam (Mare)
Important: This tool models only Extension, Agouti, and Cream. It does not include Grey, Dun, Roan, Silver, Champagne, Pearl, Mushroom, Pinto patterns, or modifiers.
How this horse color calculator works
This page is designed for breeders, students, and horse enthusiasts who want a quick and practical way to estimate foal coat color outcomes. You choose genotypes for each parent, and the calculator applies basic Mendelian inheritance to generate probabilities.
The result is not a guarantee of what color a foal will be, but it is a strong probability estimate based on the genes selected. If both parents are genetically tested, these predictions can be very useful for planning and education.
Core genes used in this calculator
1) Extension (E/e)
The Extension locus controls whether black pigment can be produced.
- E = allows black pigment
- e = red-only pigment when homozygous (ee)
A horse with ee is chestnut/sorrel regardless of Agouti genotype.
2) Agouti (A/a)
Agouti affects where black pigment is expressed, but only when the horse has at least one E.
- A = restricts black pigment to points (bay pattern)
- a = no restriction, allowing a black body color
If a horse has E_ and A_, it is generally bay-based. If it has E_ and aa, it is black-based.
3) Cream (Cr/n)
The Cream gene dilutes base color. One copy gives a single dilution, two copies give a double dilution.
- n/n = no cream dilution
- Cr/n = single cream dilution
- Cr/Cr = double cream dilution
Base color + cream outcomes
| Base Color | n/n (no cream) | Cr/n (single cream) | Cr/Cr (double cream) |
|---|---|---|---|
| Chestnut | Chestnut / Sorrel | Palomino | Cremello |
| Bay | Bay | Buckskin | Perlino |
| Black | Black | Smoky Black | Smoky Cream |
How to use this tool effectively
- Use verified genotype results whenever possible (lab test results are best).
- If genotype is unknown, use likely options and compare outputs.
- Focus on probabilities over single outcomes. Even 75% is not 100%.
- Remember that appearance can be influenced by additional genes not modeled here.
Example scenarios
Chestnut x Chestnut
If both parents are ee and no cream is present, foals will be chestnut/sorrel. If one parent carries cream, palomino becomes possible. If both carry cream, double-dilute outcomes can appear.
Bay x Black with one cream carrier
A bay parent carrying Aa and a black parent with aa can produce bay or black-based foals if Extension allows black pigment. Adding one cream copy in either parent introduces buckskin or smoky black possibilities.
Limitations and important notes
This calculator intentionally stays simple and educational. Real-world coat color prediction can include many additional loci and modifiers. For some breeding programs, you may also need to consider Grey (which can mask base color with age), Dun, Roan, Silver, Champagne, Pearl, and pattern genes (such as tobiano or frame overo).
Coat color can be fun and useful to predict, but responsible breeding should prioritize health, temperament, conformation, and welfare over color outcomes alone.
Final thoughts
A good horse color calculator gives you a practical probability map, not a promise. Use it as a decision-support and learning tool, then combine it with proper genetic testing and expert veterinary guidance when making breeding decisions.