Dog Age Calculator
Convert dog years to human years based on your dog’s age and size, and find out which life stage your dog is in.
About the Dog Age Calculator
The old rule of “one dog year equals seven human years” is a myth. Dogs grow up very fast in their first two years, and large breeds age faster than small ones. This dog age calculator uses a size-based chart recommended by vets to give your dog’s age in human years.
How to Use the Dog Age Calculator
- Enter your dog’s age in years (you can use decimals, for example 1.5).
- Choose your dog’s adult size.
- Press Calculate to see the age in human years and the life stage.
Formula and How It Works
The first year of a medium dog’s life equals about 15 human years and the second adds about 9 more (24 in total). After that, each year adds about 4 human years for small dogs, 5 for medium, 6 for large and 7 for giant breeds. A newer DNA-based formula, 16 × ln(dog age) + 31, is shown for comparison.
Frequently Asked Questions
How old is a 10-year-old dog in human years?
About 56 for a small dog, 64 for a medium dog, 72 for a large dog and up to 80 for a giant breed.
When is a dog considered a senior?
Small dogs around 10–12 years, medium dogs around 8–10, and large or giant breeds from about 6–8 years.
Results are estimates for general information and are not medical or veterinary advice. Please speak to a qualified professional about your own situation.