Cat Age Calculator
Last updated: 2026-06-25
A cat's human age is about 15 years at age 1 and about 24 years at age 2, after which about 4 human years are added per year.
The formula is human age = 24 + (cat age − 2) × 4. (For cats aged 2+, an estimate for reference only.)
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Human age conversion
0 yrs
The human-age conversion is an estimate for reference only that varies by individual. For a health assessment, consult a licensed veterinarian.
How to use
- Enter cat age — Enter your cat's age in years (or as a decimal).
- View the result — Press calculate to see the human-age conversion and life stage.
How to convert cat years to human years
Cats pass quickly through the equivalent of human adolescence and early adulthood in their first two years. According to the conversion used by the American Animal Hospital Association (AAHA) and the American Association of Feline Practitioners (AAFP), age 1 is about 15 human years and age 2 is about 24. After age 2, about 4 human years are added each year.
For example, a 5-year-old cat is 24 + (5 − 2) × 4 = 36 human years, and a 10-year-old is 24 + (10 − 2) × 4 = 56. For cats under 1 year, growth toward about 15 human years over the first year is converted proportionally.
| Cat age | Human age | Life stage |
|---|---|---|
| 1 yr | 15 | Junior |
| 2 yrs | 24 | Young adult |
| 4 yrs | 32 | Adult |
| 7 yrs | 44 | Mature |
| 11 yrs | 60 | Senior |
| 15 yrs | 76 | Super senior |
| 20 yrs | 96 | Super senior |
Unlike dogs, cats have no breed-size brackets, so after age 2 a flat 4 human years is added per year. If you want a dog's age, use the Dog Age Calculator.
Frequently asked questions (FAQ)
How old is a 1-year-old cat in human years?
Cats grow rapidly in their first year, so a 1-year-old cat is about 15 human years and a 2-year-old is about 24. After that, about 4 human years are added per year.
Is cat age conversion the same as for dogs?
The early conversion (15 at age 1, 24 at age 2) is similar, but cats have no breed-size brackets, so after age 2 a flat 4 human years is added per year. For dogs it varies from 4 to 6 by size.
At what age is a cat considered senior?
In general, cats are considered senior at age 11 (about 60 human years), and 15 and over are classed as super senior. In the senior years, regular kidney and thyroid checkups are important.
Is age conversion different for indoor and outdoor cats?
The conversion formula itself is the same, but indoor cats have a longer average lifespan because of lower accident and disease risk. This calculator applies the same formula regardless of environment, as an estimate for reference only.
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Last updated: 2026-06-25