Dog Age Calculator

Dog's age, years

Breed size

Result

In human years39
Life stageвзрослая
Human years per year5
Typical lifespan13
Roughly remaining8

This result is informational only and is not professional advice.

Multiplying by seven was never right

A dog's age in human terms adjusted for breed size, the life stage it corresponds to and typical life expectancy.

The seven-to-one rule came from dividing an average dog's lifespan into a human one, and it falls apart on inspection. A one-year-old dog is fully grown and able to breed; a seven-year-old child plainly is not.

The real pattern is different: the first year is worth roughly fifteen human years, the second nine, and everything after that depends on size. Small breeds age slowly and live long — four human years per year against seven and a half for giants.

What this calculator shows

Age in human years adjusted for breed size
The life stage: puppy, adult or senior
Typical life expectancy for that size and roughly how much is left

What to keep in mind

The figures are averages; individuals within a size band vary, and a particular dog's health matters more than the statistic.
Life expectancy assumes a house dog with normal care and regular veterinary visits.

FAQs

Why do large dogs live shorter lives?

Biology has no complete answer, but the correlation is firm: the bigger the breed, the faster the growth and the earlier age-related disease begins. A Great Dane manages 8-9 years, a chihuahua up to 17.

When is a dog considered senior?

Around ten for small breeds, eight for medium, six for large and five for giants. From then on vets recommend check-ups twice a year.

Where did the multiply-by-seven rule come from?

From dividing a seventy-year human lifespan by a ten-year canine one. There is no biology behind it, and it goes most wrong in the first two years.

How do I estimate the age of a rescue dog?

From the teeth: white and unworn in a young dog, tartar and worn incisors by five, clear wear by eight. A vet can usually place it within a year.

Worked example

A five-year-old medium breed

Input: 5 years, medium 10-25 kg

Output: About 39 human years

Note: A giant breed at the same five years would read 46. That difference is why large dogs live shorter lives — they move through every stage faster.

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Dog Age Calculator

Result

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