foal color calculator

How This Foal Color Calculator Works

This calculator estimates probable foal coat colors using a simplified Mendelian model across four major loci: Extension, Agouti, Cream, and Gray. It computes all possible allele combinations from sire and dam, then converts those genotypes into likely visible phenotypes.

Genes included in this model

• Extension (E/e): Controls black pigment production. Foals with ee are chestnut-based.
• Agouti (A/a): Restricts black pigment to points; if black pigment is present, A_ tends toward bay and aa tends toward black.
• Cream (Cr/n): Dilution gene. One copy can produce buckskin, palomino, or smoky black. Two copies create stronger dilution (cremello, perlino, smoky cream).
• Gray (G/g): Dominant progressive depigmentation gene. G_ foals are labeled as gray over a base coat color.

Quick Interpretation Guide

If your result says “Gray (born Bay)”, that means the foal is genetically gray and will likely lighten over time, but was born with a bay base color. This is a common and useful distinction for breeders tracking early coat identification versus adult appearance.

Single cream vs double cream

• Single cream (n/Cr): Chestnut → Palomino, Bay → Buckskin, Black → Smoky Black.
• Double cream (Cr/Cr): Chestnut → Cremello, Bay → Perlino, Black → Smoky Cream.

Example Scenario

Suppose both sire and dam are Ee Aa n/Cr gg. The offspring can inherit chestnut, bay, or black base colors, and each can potentially be diluted by cream. Because neither parent carries gray in this example, no gray foals are predicted. The calculator will break these outcomes into percentages so you can compare likely vs less likely color outcomes at a glance.

Important Limitations

This tool is educational and intentionally simplified. Real-world equine coat color outcomes may involve additional loci and modifiers such as dun, champagne, silver, roan, tobiano, sabino, frame overo, leopard complex, and other pattern genes. Test-based breeding decisions should use full genetic panels and expert review when needed.

Best use cases

• Planning breeding combinations at a high level
• Learning how dominant and recessive inheritance changes foal outcomes
• Teaching students and owners basic horse color genetics

Use this calculator as a fast first-pass estimate, then confirm with DNA testing and breed-specific genetics knowledge.