Cat Age Calculator — Cat Years to Human Years
CalculatorA cat age calculator converts cat years to human years using the common veterinary rule: 15 for the first year, +9 for the second, then +4 per year.
What is it
Cats mature quickly: a 1-year-old cat is roughly a 15-year-old human and a 2-year-old about 24. After that, each cat year adds about 4 human years. This conversion is the one used by International Cat Care and the AAHA/AAFP feline life stage guidelines. Actual aging varies with breed, indoor or outdoor life, and health.
human age ≈ 15 (year 1) + 9 (year 2) + (cat age - 2) × 4 (for cats 2 years and older)
How to use
- 1Enter the cat’s age in years.
- 2Press calculate.
- 3Check the human-age estimate and life stage reference.
Reference
| Cat age | Human age |
|---|---|
| 1 yr | 15 |
| 2 yr | 24 |
| 5 yr | 36 |
| 10 yr | 56 |
| 15 yr | 76 |
| 20 yr | 96 |
Sources & standards
- How to tell your cat’s age in human years - International Cat Care
- 2021 AAHA/AAFP Feline Life Stage Guidelines - AAHA / AAFP
FAQ
How old is a 10-year-old cat in human years?
About 56: 24 for the first two years plus 8 × 4.
Does breed size change the conversion like it does for dogs?
No. Cats vary much less in body size than dogs, so the same 15 + 9 + 4-per-year rule is used for all breeds.
Is cat age calculator input sent to a server?
No. This tool runs in your browser and does not send input to a server.