Cat's age
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How this calculator works
Cats grow up quickly: by the end of the first year a cat is roughly equivalent to a 15-year-old person, and by two years to a 24-year-old. After that each cat year adds about four human years. Knowing the life stage helps with choosing food and planning vet check-ups, since older cats benefit from more frequent visits.
Formula
- 15 human years at age 1
- 24 human years at age 2
- +4 human years for each year after 2
- Ages under 2 are interpolated
Worked example
A 10-year-old cat
- Cat's age
- 10 years
ResultAbout 56 human years
A 10-year-old cat. Life stage: Mature adult.
Things to keep in mind
- Individual cats age differently. Indoor cats typically live longer than outdoor cats.
Frequently asked questions
How old is a 10-year-old cat in human years?
About 56: 24 for the first two years plus 4 for each of the next eight.
When is a cat considered senior?
Veterinary guidelines class cats over 10 years as senior. Many vets recommend check-ups twice a year from then on.
How long do cats live?
Indoor cats commonly live 12 to 18 years, and some reach their twenties.
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Results are estimates based on the values you enter and the published method shown above. They do not replace professional medical, financial or legal advice. Method reviewed October 7, 2026. About this site