Dog Age Calculator - Dog Years to Human Years by Size
Dog Age Calculator
Find out how old your dog is in human years
Size Matters
Bigger dogs age faster after the first years, so the main answer uses the size chart.
Three Methods Compared
See the size chart, the epigenetic formula and the old 7x rule side by side.
Life Stage
Learn whether your dog is a puppy, young adult, adult or senior.
Full Privacy
Everything is calculated in your browser.
Why Not Just Multiply by Seven?
The familiar "one dog year equals seven human years" is a rough average, and it gets the early years wrong: a one-year-old dog is closer to a teenager of about 15 than to a 7-year-old. The size-based chart gives a dog 15 human years at one, 24 at two and 4 more each year after that up to 5 for medium, 6 for large and 7 for giant dogs, so a 10-year-old medium dog is about 60 and a giant one about 78.
In 2020, researchers at the University of California San Diego compared how DNA methylation changes in dogs and people and proposed human age = 16 × ln(dog age) + 31, fitted to Labrador retrievers. It is a single-breed model, so it is best treated as another point of comparison. Lifespan varies with breed and health, and none of these methods replaces advice from your vet.
Key Takeaways
- Puppies handled: Works from one month of age.
- Up to 30 years: The size chart continues past 16 years.
- Just a guide: Ask your vet about your own dog.