How this calculator works
Cats mature very quickly in their first two years — a 1-year-old cat is already roughly equivalent to a 15-year-old human, and a 2-year-old cat to a 24-year-old human. After that, aging slows down and each additional cat year adds about 4 human years. Unlike dogs, cat aging doesn't vary much by breed size, so this calculator uses a single curve for all cats.
General life stage guide
- Kitten (0–1 year): rapid growth, equivalent to childhood through the teenage years.
- Young adult (1–6 years): equivalent to a human in their 20s to early 40s.
- Mature adult (7–10 years): equivalent to a human in their mid-40s to late 50s.
- Senior (11–14 years): equivalent to a human in their 60s to early 70s.
- Geriatric (15+ years): equivalent to a human in their late 70s and beyond.
Indoor cats typically live 13–17 years, sometimes longer. This tool is for general information only and isn't a substitute for veterinary advice about your specific cat's health.
Sources
Quick reference: cat age in human years
| Cat's age | Human-year equivalent | Life stage |
|---|---|---|
| 1 year | 15 | Kitten to young adult |
| 2 years | 24 | Young adult |
| 3 years | 28 | Young adult |
| 5 years | 36 | Young adult |
| 7 years | 44 | Mature adult |
| 10 years | 56 | Mature adult |
| 12 years | 64 | Senior |
| 15 years | 76 | Geriatric |
| 18 years | 88 | Geriatric |
| 20 years | 96 | Geriatric |
After age two, every additional cat year adds about four human years. The full formula is published in our methodology.
Frequently asked questions
Is 1 cat year equal to 7 human years?
No. That rule averages out badly at both ends. A 1-year-old cat is roughly equivalent to a 15-year-old human and a 2-year-old cat to a 24-year-old, because cats reach social and physical maturity very quickly. Only after age two does the pace settle to roughly four human years per cat year.
How old is a 10-year-old cat in human years?
About 56. Using the same curve, a 12-year-old cat is about 64, a 15-year-old about 76, and a 20-year-old about 96.
When is a cat considered a senior?
Current AAHA/AAFP life stage guidelines treat roughly 10 years and up as senior, with cats aged about 7 to 10 described as mature adults. Senior status is a prompt for more frequent wellness checks and bloodwork, not a sign anything is wrong.
Do cats age differently depending on breed?
Far less than dogs do, which is why this calculator uses a single curve for all cats. Adult domestic cats cluster in a narrow weight range compared with the gap between a Chihuahua and a Great Dane. The main exception is large slow-maturing breeds such as the Maine Coon, which can take three to four years to reach full size; the calculator does not model that, and we say so in our methodology. See also Cost of Owning a Maine Coon.
How long do indoor cats live?
Indoor cats commonly live 13 to 17 years, and reaching the early twenties is not unusual. Outdoor access lowers average lifespan considerably through traffic, predation, fights, and infectious disease.