Dog and cat years to human years
The old “multiply by seven” rule is a myth. Dogs mature fast in the first two years, and large breeds age faster than small ones after that. Cats follow a smoother curve, reaching human-equivalent adulthood by age two.
| Pet age (years) | Cat ≈ human | Small dog ≤10 kg | Medium dog 10–25 kg | Large dog >25 kg |
|---|---|---|---|---|
| 0.5 | 8 | 6 | 7 | 8 |
| 1 | 15 | 15 | 15 | 15 |
| 2 | 24 | 24 | 24 | 24 |
| 3 | 28 | 28 | 28 | 32 |
| 4 | 32 | 32 | 34 | 38 |
| 5 | 36 | 36 | 40 | 45 |
| 6 | 40 | 40 | 45 | 50 |
| 7 | 44 | 44 | 50 | 56 |
| 8 | 48 | 48 | 54 | 62 |
| 9 | 52 | 52 | 60 | 68 |
| 10 | 56 | 56 | 66 | 74 |
| 12 | 64 | 64 | 77 | 86 |
| 14 | 72 | 72 | 88 | 98 |
| 16 | 80 | 80 | 99 | 110 |
Notes
- Based on AVMA-style guidance; individual breeds vary.
- The first year of a medium dog ≈ 15 human years; year two adds ~9 more.
- Large breeds are seniors at 6–7, small breeds at 10+.
Frequently asked questions
- Is one dog year really seven human years?
- No. A one-year-old dog is closer to a 15-year-old human, and aging slows after that — the 7× rule badly overestimates later years.
- How old is a 10-year-old cat in human years?
- About 56 human years, using the standard feline curve where a 1-year-old cat ≈ 15 and a 2-year-old ≈ 24.
- Why do large dogs age faster?
- Research links large size to faster aging and shorter lifespans — a Great Danes' cells accumulate damage quicker, so tables age them faster after year two.