How to calculate a dog's age in human years?

The estimate uses a base of 10.5 human years for the first two years of the dog's life, adjusting subsequent years according to the animal's size and weight, as large dogs age faster than small ones.

Why does the dog's size influence human age?

Unlike other animals, canine longevity is inversely proportional to size: large breeds expend more biological energy to grow and maintain their metabolism, which accelerates the aging process compared to small dogs.

Dog Age Calculator

Discover your dog's equivalent age in human years by considering its age and size.

Insert Pet Info

How does this tool work?

Enter dog’s age in years: Provide the dog’s actual age (can be fractional).
Select dog size (optional): Small, medium, or large breed influences aging rate.
Convert: The tool applies a breed-size-aware formula to compute human-equivalent age.
Interpret life stage: See whether your dog is a puppy, adult, or senior.

Dog age conversion accounts for the fact that smaller dogs tend to live longer and age differently than larger breeds. A common approximation: a 1-year dog ≈ 15 human years; a 2-year dog ≈ 24 human years; each additional year ≈ 5–7 human years depending on size.

How is the estimate calculated?

Unlike felines, canine aging varies drastically according to physical size. Large breed dogs tend to age faster than small breeds.

The calculation base uses an average of 10.5 human years for the first two years of life, adjusting the following years based on the animal's weight. We use the latest canine longevity techniques to provide this result.

If you also own a feline, you can check our cat age calculator, which uses a species-specific calculation method.

Average Equivalence Table (Medium Size - 10kg/22lbs)

Life Stage	Animal Age	Human Age (Equivalent)
Puppy	6 to 9 months	0 to 14 years
Young Adult	1 to 7 years	14 to 49 years
Mature Adult	7 to 12 years	49 to 84 years
Senior	12 to 15 years	74 to 83 years
Geriatric	Above 15 years	Above 83 years

Important Notice

If you are concerned about your pet's health, always seek a veterinarian. Only a professional can accurately evaluate general health and define the real longevity of your friend.