Pet Age Calculator
Convert cat years to human years, or human years back to cat years. The same tool does dogs, rabbits and horses. Cats and dogs of the same calendar age do not share one human-year number.
Life stage
Pet age calculator
Cat years to human years, or the reverse. Dogs use size because large breeds age faster after adulthood. Cats and dogs of the same birthday are not the same in human-year terms.
Cat and dog: 15 in year one, 9 in year two, then about 4 a year for cats and 4–5 for dogs by size. Rabbit: about 21 then 6. Horse: about 6.5 in the first two years then 2.5. These are rules of thumb, not lab values.
Common questions
How do you calculate cat years to human years?
Year one is about 15 human years, year two adds about 9, then each later year adds about 4. A 7-year-old cat is about 44. A 13-year-old cat is about 68.
How do I convert human years to cat years?
Switch the tool to Human to pet. Fifteen human years is about one cat year. Twenty-four human years is about two cat years. After that, add one cat year per four human years.
Do cats and dogs age the same?
No. The first two years are close. After that a medium dog adds about 4.5 human-year equivalents per calendar year and a cat adds about 4. Large dogs age faster than cats.
How old is a 15 year old cat?
About 76 in human-year terms on the common 15 / 9 / 4 rule. That is a senior cat, not a calculation of remaining lifespan.