How To Predict Foal Coat Color With a Simplified Genetics Model
What This Horse Color Calculator Actually Models
Foal color prediction is only as reliable as the genes included in the model. This calculator intentionally focuses on the three gene groups it actually supports: Extension, Agouti, and Cream. That keeps the result specific and readable instead of pretending to cover every possible modifier in equine color genetics.
How To Use This Calculator
Choose basic mode if you only want to select each parent's base color and whether a cream dilution is present.
Choose advanced mode if you know the sire and dam genotypes for Extension, Agouti, and Cream and want a more precise probability model.
Enter both parent profiles, then review the possible foal colors table, total probability, and the gene-rule notes together.
Use the breeding notes as a reminder that the model is limited to the genes shown in the calculator.
How the Foal Color Probabilities Are Built
Foal color probability = matching offspring genotype combinations / all modeled allele combinations
In advanced mode, the calculator combines one allele from each parent for Extension, Agouti, and Cream, then maps each resulting genotype to a phenotype such as bay, buckskin, or cremello. The displayed probabilities reflect the share of modeled genotype combinations that produce each visible color outcome.
In basic mode, the calculator first assigns simplified default genotypes to the selected parent colors before it runs the same probability logic. That makes the quick mode useful for rough planning, but advanced mode is the better choice when you know carrier status or have genetic test results.
Useful Horse-Color Scenarios
Checking whether a mating can produce chestnut
When both parents carry or express chestnut genetics, the probability table makes it easier to see whether chestnut remains possible or guaranteed under the modeled genes.
Comparing single-cream and double-cream outcomes
A parent carrying one cream allele can create diluted colors like palomino or buckskin, while double-cream outcomes require the right combination from both parents. The table makes those outcomes visible quickly.
Moving from a color guess to genotype-based planning
If a parent looks bay but may hide recessive alleles, advanced mode gives a more defensible probability estimate than relying on appearance alone.
How To Read the Result
The possible foal colors table is the core output. Each row shows a modeled color, a percentage probability, and a short description. The probabilities should sum to 100%, and the possible-color count tells you how many modeled phenotypes remain after combining the parent inputs.
The genetics notes and breeding note text matter because they explain the model boundary. If a breeding decision depends on genes outside Extension, Agouti, and Cream, treat the result as incomplete rather than exact.
Horse-Color Prediction Tips
Use advanced mode when you have genetic testing or known carrier information
Treat basic mode as an approximation because hidden recessive alleles are simplified
Remember that this calculator does not currently model every dilution or pattern gene
Read the probability table as a breeding probability, not a guarantee for a single foal
Use real breeding, health, and conformation criteria alongside color goals
Breeding Note
This calculator is an educational genetics estimator only. It does not replace genetic testing, veterinary guidance, breed-registry rules, or a full breeding evaluation that includes genes and traits beyond the modeled color system.
Frequently Asked Questions
Basic mode uses simplified default genotypes based on the selected parent colors, while advanced mode lets you enter the actual Extension, Agouti, and Cream genotypes directly.
No. Two modeled chestnut parents are treated as `ee`, so they do not produce the dominant `E` allele needed for bay or black outcomes.
Because this calculator is limited to the Extension, Agouti, and Cream genes. Other modifiers and pattern genes are outside the current model.
No. It means that color has a 25% probability under the modeled genetics. Individual foals are still single outcomes, not averaged breeding batches.
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