Dog Age Calculator
Convert your dog's age into human years, adjusted for size.
About the Dog Age Calculator
The widely used veterinary rule of thumb (cited by the AVMA and UC Davis): a dog's first year equals about 15 human years and the second adds about 9. After that each year adds about 5 for a medium-sized dog; small breeds age more slowly in later life (about 4 a year) and large breeds faster (about 6 or more).
A 2020 study of DNA methylation in Labrador retrievers (Wang et al., Cell Systems) proposed human age = 16 × ln(dog age) + 31, which shows dogs ageing very fast early on.
The formula
AVMA: 15 + 9 + ~5 × (years − 2); epigenetic: 16 ln(age) + 31
Worked example
Example: Human-equivalent age = 49 years
- Inputs: Dog's age: 7 years; Size when grown: Medium.
- Formula: AVMA: 15 + 9 + ~5 × (years − 2); epigenetic: 16 ln(age) + 31
- Result: Human-equivalent age = 49 years
Questions people ask
Is 1 dog year 7 human years?
No, that old rule underestimates early ageing and overestimates later.
When is a dog a senior?
Around 7 years for many dogs, earlier for giant breeds.