Turn your cat’s age into human years and see which life stage your cat is in.
Cats grow up fast. By their first birthday they’re roughly as mature as a 15-year-old person, and by two they’re like a young adult in their mid-twenties. After that, each cat year counts for about four human years. This calculator follows the chart used by feline vets, and it accepts months too, which helps for kittens.
How do you convert cat years to human years?
The first year equals about 15 human years and the second adds 9 more, making 24. After that, add about 4 human years for each cat year. So a 6-year-old cat is roughly 24 + (4 × 4) = 40 in human years.
Cat age chart
| Cat age | Human age | Life stage |
|---|---|---|
| 3 months | 4 | Kitten |
| 6 months | 10 | Kitten |
| 1 year | 15 | Young adult |
| 2 years | 24 | Young adult |
| 5 years | 36 | Mature adult |
| 8 years | 48 | Mature |
| 11 years | 60 | Senior |
| 15 years | 76 | Senior |
| 20 years | 96 | Senior |
What each life stage means for care
Kittens need frequent meals, vaccinations and plenty of play. Young and mature adults do well with yearly check-ups and weight control. Senior cats benefit from check-ups every six months, since kidney, thyroid and dental problems become more common.
How to use the Cat Age Calculator
Enter your cat's age
Type the years, and months if you know them.
Read the human age
The human-equivalent age appears in large text, with your cat’s life stage underneath.
Frequently asked questions
How old is a 1-year-old cat in human years?
About 15 human years.
How old is a 10-year-old cat in human years?
About 56 human years.
At what age is a cat a senior?
Cats are usually considered senior from around 11 years, and some vets start senior check-ups from 10.
How long do indoor cats live?
Indoor cats commonly live 12 to 18 years, and many reach their twenties.
Do all cat breeds age the same?
Mostly yes. Unlike dogs, cats don’t vary much in size, so one chart fits nearly all breeds.
Sources and further reading
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Last reviewed: October 2026