Dog & Cat Age Calculator

Convert your dog’s or cat’s age into human years, adjusted for dog size.

How old is my dog in human years?

A dog’s first year equals about 15 human years and its second about 9 more (24 in total); after that, each year adds about 4–7 human years depending on size, because larger breeds age faster. A 5-year-old medium dog is about 39 in human years.

Cats

Cats follow a similar curve: 15 at one year, 24 at two, then about 4 human years per cat year — a 10-year-old cat is roughly 56.

The old “multiply by 7” rule overestimates young pets and underestimates old ones.

Frequently asked questions

When is a dog a senior?

Giant breeds from about 5–6 years, large dogs from 7–8, small dogs from about 10–12.

Is this exact?

No, it is a veterinary rule of thumb; breed and health matter.

Is it free?

Yes.