Dog Age Calculator — Dog Years to Human Years
Estimate your dog's age in human years using AVMA-aligned size-adjusted formulas — the simple ×7 myth is wrong. Larger breeds age faster than smaller ones.
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Frequently asked questions
Why isn't it just dog years × 7?
The ×7 rule is folklore — it dates to a 1950s estimate and doesn't match observed canine aging. Real dog aging is fastest in the first year (puberty hits around 6–12 months) and slows down. By human equivalent, a 1-year-old dog is roughly 15, a 2-year-old is ~24, and each subsequent year adds 4–7 human years depending on size. The ×7 rule wildly overestimates age in years 1–3 and underestimates in years 8+ for large breeds.
Do small dogs really live longer?
Yes, substantially. Small breeds (<20 lbs) average 14–16 years; medium 12–14; large 10–12; giant 7–10. The exact mechanism is debated — proposed factors include faster cellular turnover in larger bodies, higher IGF-1 levels in big breeds, and selective breeding for fast growth in large breeds. The size-longevity inverse relationship is unique to dogs among mammals (in most species, larger = longer-lived).
When is a dog considered senior?
Veterinary consensus: small breeds ~11+ years, medium 10+, large 8+, giant 6+. Senior dogs benefit from twice-yearly vet exams, joint supplements, weight management (overweight seniors have far more arthritis), and adjusted nutrition (often lower-calorie, higher-protein). Many vets switch dogs to 'senior' wellness plans at these thresholds even if the dog seems young and energetic.