Based on AVMA veterinary guidelines. First year = 15 human years, second year = +9, each additional year varies by breed size for dogs. Cats age ~4 human years per year after age 2.
Convert your dog or cat's age to human years instantly. Enter your pet's age, breed size, and species to get an accurate human-equivalent age. Uses AVMA veterinary formulas — the old multiply-by-7 rule is outdated. Free pet age calculator for dogs and cats.
Select whether your pet is a dog or a cat. Dogs and cats age differently, so species selection is important for accurate results.
Enter your pet's age in years and select the months. For dogs, select the breed size (Small, Medium, Large, or Giant) as larger breeds age faster. Cats use a single formula regardless of breed.
Click Calculate to see your pet's human-equivalent age and life stage. The result uses AVMA-approved formulas that are far more accurate than the old 7:1 ratio.
Q: How is dog age calculated?
A: AVMA formula: First year = 15 human years, second year = +9 (total 24). After year 2: Small breeds +4/year, Medium +5/year, Large +6/year, Giant +7/year.
Q: How is cat age calculated?
A: Cats: First year = 15 human years, second year = +9 (total 24). After year 2: each year = +4 human years, regardless of breed.
Q: Why not multiply by 7?
A: The old multiply-by-7 rule is outdated and inaccurate. Modern veterinary science shows that pets age much faster in their early years and the rate varies by breed size. Our calculator uses AVMA-approved formulas.