Convert your dog’s age into human years, adjusted for its size.
The Dog Age Calculator converts your dog’s age into the equivalent human age, using a commonly cited veterinary approximation that accounts for breed size.
Dogs mature quickly in their first two years, then age more slowly — and larger breeds tend to age faster in their later years than smaller ones. This is an approximation for general interest, not a veterinary assessment.
Year 1 = 15 human years. Year 2 adds 9 more (total 24 by age 2). Each year after that adds a size-based factor: about 4 years for small dogs, 5 for medium, 6 for large, and 7 for giant breeds.
A 5-year-old medium-sized dog is about 24 + (3 × 5) = 39 in human years.
Modern formulas (more accurate than the old "multiply by 7" rule) account for the fact that dogs age very fast in their first two years, then more slowly afterward, and often factor in breed size.
Larger dog breeds tend to have shorter overall lifespans and age faster in their later years compared to smaller breeds, despite maturing at similar or slightly slower initial rates.
No — it's an old oversimplification. A 1-year-old dog is already roughly equivalent to a 15-year-old human in terms of physical maturity, not 7.