Convert your pet’s age to human years. This free pet age calculator covers dogs by size, cats and rabbits, showing the human-equivalent age and life stage for a more accurate picture than the old ×7 rule
Your pet
years
Choose your pet (dogs are split by size, since larger dogs age faster) and enter their age in years. You can use decimals, like 0.5 for six months.
In human years
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Enter your pet’s age
Pet age
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Human-equivalent
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Life stage
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Human years / pet year
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Pets don’t age at a steady “7 years per year” — the first couple of years count for much more, then the rate settles. These are estimates; large dogs age faster than small ones, and breed and health matter too.
Use this free pet age calculator to convert your pet’s age into human years. It covers dogs (by size), cats and rabbits, since different animals age at different rates.
What this pet age calculator does
A pet age calculator estimates your pet’s human-equivalent age. The old “multiply by 7” rule is too simple — pets age fast in their first two years, then more slowly, and larger dogs age quicker than small ones.
How pet years convert to human years
Dogs/cats: year 1 ≈ 15, year 2 ≈ +9 (24 total)
then per year: small dog +4, medium +5, large +6, cat +4
So a 5-year-old medium dog is about 39 human years, a large dog about 42, and a 5-year-old cat about 36.
Pet age at a glance
Pet age
Medium dog
Cat
1 year
15
15
2 years
24
24
5 years
39
36
10 years
64
56
Why size and species matter
Small dogs often live longer and age more slowly than large breeds, so a giant breed at 8 is “older” in human terms than a toy breed at 8. Cats tend to age slightly slower than dogs after the first two years, and rabbits follow their own, shorter timeline.
How to use the pet age calculator
Choose your pet — dog by size, cat or rabbit.
Enter their age in years (decimals are fine).
Read the human-equivalent age and life stage.
Pet Age FAQ
How do I convert pet years to human years?
Pets age fast early on: roughly 15 human years in year one and 24 by year two, then about 4–6 more per year depending on species and size.
Is one pet year really seven human years?
No — that's an oversimplification. The first two years count for much more, and the rate then settles and varies by size and species.
Why are dogs split by size?
Larger dogs age faster and have shorter lifespans, so a big breed reaches "senior" sooner than a small one of the same age.
How old is a 5-year-old dog in human years?
About 36 for a small dog, 39 for a medium dog and 42 for a large dog, using common conversion estimates.
Does it work for cats and rabbits?
Yes. Cats age slightly slower than dogs after year two, and rabbits follow their own shorter timeline — both are included.
Is the pet age calculator free?
Yes, this pet age calculator is completely free, needs no sign-up, and gives instant results in your browser.
