Your pet’s age in human years
How old your dog or cat is in human years, which life stage that is and what matters right now — by the veterinary guidelines, not the «×7» myth.
How we count
The first year of life ≈ 15 human years, the second adds ≈ 9 (so 24 at two), then each year adds a few more: +4 for cats (AAHA/AAFP Feline Life Stage Guidelines).
For dogs it depends on size: +4 a year for a small dog, +5 medium, +6 large, +7 giant. A simplified linear table after AVMA and the AKC; the real AKC chart is not strictly linear past year five — big dogs age faster.
The «×7» myth is a 1950s rule of thumb: people lived to ~70, dogs to ~10. It ignores that a dog’s first year is already adolescence, and that a big dog ages faster than a small one. The tables above are closer, though still approximate.
What science says: in 2020 Wang and colleagues (Cell Systems) derived a formula from DNA methylation: human age = 16·ln(dog age) + 31. By it a one-year-old dog is 31 and a five-year-old 57. A study on Labradors — hence its own line.
Tables
| Pet years | Human |
|---|---|
| 1 | 15 |
| 2 | 24 |
| 3 | 28 |
| 5 | 36 |
| 7 | 44 |
| 10 | 56 |
| 12 | 64 |
| 15 | 76 |
| Pet years | Small | Medium | Large | Giant |
|---|---|---|---|---|
| 1 | 15 | 15 | 15 | 15 |
| 2 | 24 | 24 | 24 | 24 |
| 3 | 28 | 29 | 30 | 31 |
| 5 | 36 | 39 | 42 | 45 |
| 7 | 44 | 49 | 54 | 59 |
| 10 | 56 | 64 | 72 | 80 |
| 12 | 64 | 74 | 84 | 94 |
| 15 | 76 | 89 | 102 | 115 |
Sources
- AAHA/AAFP Feline Life Stage Guidelines (2021) — feline life stages
- AAHA Canine Life Stage Guidelines (2019) — canine life stages
- AVMA — «How old is my pet in people years?»
- AKC — the dog age chart by size
- Wang et al., Cell Systems, 2020 — the epigenetic formula 16·ln(age) + 31
The tables are approximate: the age in human years depends on breed, weight and health. Settle the life stage and the check-up plan with your vet.