Dog age in human years

Convert your dog's age to human years with a size-adjusted veterinary method — not the old “multiply by 7” myth.

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Medium (9–23 kg / 21–50 lb)

Work it out in 3 simple steps

1

Enter your dog's age

Type the age in years (and extra months if you know them).

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2

Pick the breed size

Small, medium, large or giant — bigger dogs age faster later in life.

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3

See human years

Get the human-age equivalent plus your dog's life stage instantly.

Why use this dog age calculator

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Size-adjusted method

Uses the modern veterinary chart, not the outdated “multiply by 7” myth, so large and giant breeds are handled correctly.

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Life stage

Tells you whether your dog is a puppy, adult, mature or senior, so you can plan care and vet visits.

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Years and months

Enter partial ages for young dogs — the first two years matter most for accuracy.

Instant

The result updates the moment you change the age or size.

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Private

Everything is calculated in your browser; nothing is stored or uploaded.

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Free

No sign-up and no limits — use it as often as you like.

How dog years really work

The idea that one dog year equals seven human years is one of the most stubborn pet myths. In reality a dog matures very quickly at first — a one-year-old dog is roughly equivalent to a 15-year-old human — and then ages more gradually. Breed size matters too: small dogs live longer and age slowly in later life, while large and giant breeds age faster and reach their senior years sooner.

This calculator uses a size-adjusted chartbased on veterinary guidance. Enter your dog's age and pick the breed size, and you'll get a realistic human-age equivalent along with the life stage — puppy, adult, mature or senior — so you can plan diet, exercise and vet check-ups appropriately.

Small, medium, large or giant?

As a rough guide, small is up to about 9 kg, medium is 9–23 kg, large is 23–41 kg and giant is over 41 kg. If your dog sits between two sizes, choose the heavier category. For a human age gap between two dates instead, try the age calculator or the date difference calculator.

Frequently asked questions

How do you convert dog years to human years?
This calculator uses a size-adjusted veterinary chart. A dog's first year is roughly 15 human years and the second adds about 9 more (so 2 dog years ≈ 24 human years). After that, each dog year adds between about 4 human years for small breeds and 7 for giant breeds, because larger dogs age faster later in life.
Is the “multiply by 7” rule accurate?
No. Multiplying a dog's age by 7 is a rough myth. It badly underestimates the first two years — a one-year-old dog is closer to a 15-year-old human than a 7-year-old — and it ignores breed size. This tool shows the classic figure for comparison but uses the more accurate size-based method for the main result.
Why does breed size change the result?
Small dogs live longer and age more slowly in later life, while large and giant breeds age faster and reach “senior” sooner. That's why a 10-year-old small dog and a 10-year-old giant dog are not the same in human years.
What size is my dog?
As a guide: small is up to about 9 kg (20 lb), medium is 9–23 kg (21–50 lb), large is 23–41 kg (51–90 lb), and giant is over 41 kg (90 lb). If you're between two, pick the heavier one.
When is a dog considered senior?
It depends on size, but broadly a dog is “mature” from about 7 years and “senior” from about 10. Giant breeds reach these stages earlier. The calculator shows the life stage alongside the human-age result.
Is my data saved?
No. The calculation runs entirely in your browser and no information is stored or sent to any server.

By Narender Chaudhary, Editorial & Product Lead · Updated June 2026