iHerb
SponsoredWorld's largest store for natural supplements and health foods.
Learn more →Cat Age Calculator - Cat Years to Human Years
The Cat age calculator turns your cat's age into human-equivalent years. The first year counts as about 15 human years, the second adds about 9 (24 by age two), and each year after that adds roughly 4. Enter your cat's age to see its human age in seconds.
Enter your cat's age in years to see the human-equivalent age.
How it works
How cat years compare to human years
Cats mature quickly when young, then age more steadily. A common guide puts the first year at about 15 human years and the second at about 9 more, reaching 24 by age two.
After that, each additional cat year adds roughly 4 human years, so a 5-year-old cat is around 36 in human terms.
Why these numbers are estimates
Breed, size, diet, and lifestyle all affect how a cat ages. Indoor cats often live longer than outdoor cats, so treat the result as a friendly estimate rather than a medical fact.
For health concerns, your veterinarian remains the best source of advice about your cat's life stage.
Frequently asked questions
›How is a cat's age converted to human years?
The first year counts as about 15 human years, the second adds about 9 (24 total), then each later year adds roughly 4.
›How old is a 1-year-old cat in human years?
About 15 human years, since the first year of life is the fastest stage of aging for a cat.
›How old is a 2-year-old cat in human years?
Around 24 human years, after adding about 9 to the first year's 15.
›Is this calculation exact?
No. It is a popular estimate. Breed, size, diet, and indoor or outdoor living all change how a cat ages.
›Does the formula work for kittens under one year?
It is designed for whole years. Kittens age very fast, so use the result as a rough guide only.
Recommended services
DisclosureRelated tools
Last updated: