Dog Age Calculator

Convert your dog's age to human years. Accounts for breed size — small, medium, large, and giant dogs age at different rates.

The old "multiply by 7" rule is inaccurate. Dogs age much faster in their first two years, and larger breeds age faster overall. This calculator uses size-adjusted veterinary data.

Dog's Age (years)

Enter partial years (e.g. 1.5 for 18 months)

Size Category

Breed examples — Beagle, Bulldog, Border Collie, Cocker Spaniel, Australian Shepherd

Dog Age

3 yrs

36 months

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Human Equivalent

28 yrs

Size-adjusted estimate

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Life Stage

Young Adult

Prime physical condition

Life Progress

12–14 years average lifespan

Birth

23% of average lifespan

~13 years

Year-by-Year Chart — Medium (20–50 lbs / 9–23 kg)

Dog Years	Human Equivalent	Life Stage
1 year	15 human years	Puppy
2 years	24 human years	Adolescent
3 years	28 human years	Young Adult
4 years	32 human years	Young Adult
5 years	36 human years	Young Adult
6 years	42 human years	Mature Adult
7 years	47 human years	Mature Adult
8 years	51 human years	Mature Adult
9 years	55 human years	Mature Adult
10 years	59 human years	Mature Adult
11 years	64 human years	Senior
12 years	68 human years	Senior
13 years	72 human years	Senior
14 years	76 human years	Senior
15 years	80 human years	Geriatric