Pet Age Calculator (Dog & Cat Years to Human Years)

Convert your dog or cat's age to human years using the AVMA's (American Veterinary Medical Association) non-linear, size-adjusted method — not the outdated 'multiply by 7' rule. Everything runs in your browser, so the age you enter is never sent anywhere.

Based on guidance from the AVMA (American Veterinary Medical Association).

The age you enter is processed entirely in your browser and never sent anywhere.

Enter an age and press "Calculate".

How to use

Choose Dog or Cat. For dogs, also choose a size category (small, medium, large, or giant).
Enter the age in years and months.
Press "Calculate" to see the human-year equivalent and an approximate life stage.

How it works

About the conversion method

This tool does not use the old "one pet year equals seven human years" rule of thumb. Instead it uses the non-linear method described by the AVMA (American Veterinary Medical Association), which more closely reflects how dogs and cats actually age: rapid maturation in the first one to two years, followed by a slower, steadier pace.

Shared anchor points (dogs and cats)

Age 0 = human age 0
Age 1 = human age 15
Age 2 = human age 24

The first two years are the same regardless of size or breed. For ages under 1 year and between 1-2 years, this tool linearly interpolates between these anchor points, since no official month-by-month table exists (this avoids inventing numbers that aren't backed by a source).

Conversion after year 2 (size-dependent for dogs)

Cats age at a broadly similar rate regardless of breed, so after year 2 the calculation adds 4 human years per cat year.

Dogs age at different rates depending on size — larger dogs tend to age faster. After year 2, the addition per dog year is:

Small (under 20 lb / about 9 kg): +4 years per year
Medium (20-50 lb / about 9-23 kg): +5 years per year
Large (50-90 lb / about 23-41 kg): +6 years per year
Giant (over 90 lb / about 41 kg): +7 years per year

Example: a 6-year-old medium dog (20-50 lb) is 24 + 5×(6-2) = 44 in human years.

Life stage guide

Based on the calculated human age, the tool shows a rough life-stage label. This is a general guide only, not a medical assessment.

0-12: Puppy / Kitten
13-30: Young adult
31-60: Adult
61+: Senior

About data sent

All calculations happen entirely in your browser. No data, including the age you enter, is ever sent to a server.

FAQ

Is it true that one dog year equals seven human years?

Not accurately. The old "multiply by 7" rule doesn't reflect how dogs and cats actually age — they mature very quickly in their first one to two years and then age more slowly. The AVMA recommends a non-linear method: roughly 15 human years by age 1 and 24 by age 2, with a steadier pace afterward. This tool follows that method.

Why do I need to choose a size for dogs but not cats?

Dogs age at noticeably different rates depending on their size — larger breeds tend to age faster and have shorter lifespans. Cats don't show this kind of breed-related difference in aging rate, so no size selection is needed for them.

I don't know my dog's exact weight or breed. What should I choose?

If you're not sure, "Medium" is a reasonable default for a typical household dog. For a more accurate result, check your dog's weight at the vet or look up the standard weight range for their breed.

Can I calculate the age of a very young puppy or kitten?

Yes. Set "years" to 0 and enter the age in months. For ages under 1 year, the tool linearly interpolates between age 0 (human age 0) and age 1 (human age 15).

Is the age I enter sent anywhere?

No. All calculations happen entirely in your browser — nothing is sent to any external server or API.