Convert your dog's age into human years — adjusted for breed size
Our free dog age calculator converts your dog's age into human years using a science-based formula — not the old "multiply by 7" myth. Dogs age fastest in their first two years, and smaller breeds live longer than larger ones, so we adjust the result by your dog's breed size. Find out how old your dog really is in human terms.
Based on veterinary guidance: dogs reach ~15 human years by age 1, ~24 by age 2, then add roughly 4–6 human years per dog year depending on size.
No — the "multiply by 7" rule is a myth. Dogs mature very quickly in their first two years (a 1-year-old dog is roughly 15 in human terms, and a 2-year-old about 24), then age more slowly. Our calculator uses this more accurate, vet-backed approach instead.
Smaller dogs generally live longer and age more slowly in their later years, while giant breeds age faster and have shorter lifespans. That's why a 10-year-old Chihuahua is "younger" in human years than a 10-year-old Great Dane. Select your dog's size for the most accurate result.
A 3-year-old medium-sized dog is roughly 29 human years. The first year counts as about 15, the second adds about 9 (reaching 24), and each year after that adds 4–7 depending on breed size.
Most dogs are considered senior from around 7 years old, though giant breeds may reach senior status earlier (around 5–6) and small breeds later (around 9–10). Senior dogs benefit from more frequent vet check-ups.
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