How to Convert Cat Years to Human Years

The typical life expectancy of a cat is 14 to 20 years depending on the overall health of your pet and how well it is cared for. Cats that live indoors for most of their lives can expect to live longer than cats that live outside. Because the average lifespan of a human is 75-80 years and the average lifespan of a cat is 14-15 years, many people convert cat years to human years simply by multiplying the cat's age by 5. That is, you count 5 human years for every 1 cat year. However, there is a more accurate method that takes into account a cat's reproductive maturity.

Humans finish puberty in their teens but cats can reproduce as early as one or two years. Humans reach their full adult size in their early twenties, whereas cats are finished growing by two years on average. Thus, you can convert cat years to human years with the following method:

1 year old in cat years = 15 years old in human years
2 years old in cat years = 25 years old in human years
Add 4 years human years for each additional cat year.

Example Calculations

Chester is 6 year old cat. In human years, his age is

25 + 4 + 4 + 4 + 4 = 41.

Princess is an 13 year old cat. In human years, her age is

25 + 11(4) = 69.

Instead of doing the math by hand, you can use the handy converter calculator above.

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