Pet Age in Human Years

Pets reach reproductive maturity by year 1–2, and the scale counts the first year as 15 human years — way faster than seven. After that the rate slows down, but it isn't constant either: larger dog breeds in particular age more rapidly than small ones in their middle years.

The AKC and AVMA both publish scales close to this. They're approximations and individual variation is large — this is a conversation starter, not a vet visit.

Only roughly. In dogs, size is the strongest single factor — a large breed reaches middle age years before a small one — and even within one size class, breeds differ in typical lifespan by years. Treat the number as a population average that helps frame a conversation with a vet, not as a prediction about one particular animal.

Because a pet is physically adult long before a person is. At one year a dog or cat has finished growing and can reproduce, which lines up with a human of about 15; the second year adds close to another decade of equivalent maturity. Only after that does ageing settle into the steadier few-years-per-year rate that the rest of the scale uses.