Dog Age Calculator

Your dog’s age in human years, using the size-adjusted modern scale.

Enter values

Result

In human years

The first year is worth about 15 human years, the second about 9, and each year after that depends on size.

Life stage: Adult
Typical life expectancy: 13 years
Years remaining (average): 8
Life stage progress: 38.5%
Ageing rate now: 5 human years per dog year
In dog months: 60

About the Dog Age Calculator

The old rule of multiplying by seven is wrong in both directions: dogs mature far faster in their first two years, then age more slowly — and large breeds age faster than small ones. This calculator uses the size-adjusted scale vets actually use.

Also known as: dog years calculator, how old is my dog in human years, dog age in human years, puppy age.

How to use this calculator

Enter dog’s age, size.
The result updates instantly as you type — press Calculate (or Enter) at any time.
Review the breakdown shown under the main result.
Use Copy result or Share to save the answer or send a link with your inputs.

Formula

Year 1 = 15, year 2 = +9, then +4 to +7.5 per year by size

Worked example

Using the values pre-filled in the calculator above:

Dog’s age = 5 years
Size: Medium (10–25 kg)

the calculator returns:

In human years: 39
Life stage: Adult
Typical life expectancy: 13 years
Years remaining (average): 8

Frequently asked questions

Is one dog year really seven human years?

No. That rule badly underestimates puppy development and overestimates later ageing, and it ignores size entirely.

Why do big dogs age faster?

Larger breeds grow faster and are more prone to age-related disease earlier — a Great Dane is elderly at seven, a Chihuahua is middle-aged.