Coefficient of Inbreeding Calculator for Dogs
Estimate the coefficient of inbreeding (COI/F) for a planned dog mating based on the relationship between the breeding pair.
What Is the Coefficient of Inbreeding Calculator for Dogs?
Estimate the coefficient of inbreeding (COI/F) for a planned dog mating based on the relationship between the breeding pair.
The coefficient of inbreeding (COI) measures the probability that both alleles at any gene locus in the offspring are identical by descent. Higher COI increases risk of recessive disease expression and inbreeding depression.
Every result is based on published veterinary research and breed-size-specific growth data — not generic averages. This tool is completely free, works instantly in your browser, and requires no account or sign-up.
How to Use This Calculator
Fill in the required fields above — typically your dog's weight, age, or breed size. Every field has a clear label and hint.
Press the calculate button to get your instant result. No page reload, no account needed, no waiting.
Your result appears immediately below the calculator. It includes the primary answer plus additional context where relevant.
Share, print, or save your result. Always discuss health-related results with your veterinarian before making decisions.
How It Works
The COI is calculated using the standard Wright formula: F = sum of [(0.5)^(n+m+1) x (1+FA)] across all common ancestors, where n and m are the number of generations separating the sire and dam from the common ancestor. For common relationship types, the expected COI values are well-established: first cousins = 6.25%, half-siblings = 12.5%, full siblings or parent-offspring = 25%.
Most canine geneticists recommend keeping COI below 6.25% (equivalent to first cousins) and ideally below the breed average. Many popular breeds already carry elevated population-level COI due to historical founder effects and popular sire use.
Veterinary Research
Every formula is derived from peer-reviewed veterinary studies and clinical guidelines, not guesswork or generic rules.
Instant Results
No page reload, no waiting, no account needed. Enter your details and your result appears immediately.
100% Private
All calculations happen in your browser. Nothing you enter is ever stored on our servers or shared with anyone.
Always Free
Every calculator on Doggy Calculators is and will always be completely free to use — no premium tier, no catch.
Frequently Asked Questions
Sources & References
This calculator's formulas are based on the following peer-reviewed and authoritative veterinary sources:
- Merck Veterinary Manual u2014 Genetics — Canine coat colour genetics and hereditary traits
- Kennel Club Breed Standards — Recognised breed standards and genetic characteristics
⚠️ These calculators are reference tools only. Always consult a licensed veterinarian before administering medication or making medical decisions.