Cat Age Calculator
The old “multiply by 7” rule is wrong for cats. Cats mature very fast in their first two years and then age more slowly. This calculator uses the life-stage guideline from the American Animal Hospital Association and AAFP.
Results update as you type.
- Age in human years
- 36 years
- Life stage
- Prime adult
Steps
- 24 + 4 × (5 − 2) = 36
Worked example
Example: a 5-year-old cat
- First two years = 24 human years
- Years after two: 5 − 2 = 3
- 3 × 4 = 12 → 24 + 12 = 36
A 5-year-old cat is about 36 in human years.
Formula
Year 1 = 15 human years
Year 2 = 24 human years
Each year after = +4 human years
Life stages: kitten (0–6 months), junior (7 months–2 years), prime (3–6), mature (7–10), senior (11–14), geriatric (15+).
Frequently asked questions
How old is a 10-year-old cat in human years?
About 56 (24 + 8 × 4).
Is one cat year equal to seven human years?
No. That rule undercounts young cats and overcounts old ones.
How long do indoor cats live?
Commonly 12–18 years, and many live past 20.
Last reviewed October 17, 2026 · Calculations run in your browser; nothing you enter is sent to a server.