Pick the breed and enter your dog's age. You get the human-years estimate, the life stage and, for purebreds, the age when the senior years begin.
Dog age calculator
Breed and age.
In human years, about
0
Life stage (AAHA)-
Breed life expectancy (AKC)-
Senior from about-
How it works
Human years. In 2020, researchers at UC San Diego compared age-related DNA changes in 104 Labrador Retrievers with those in people and proposed: human age = 16 x ln(dog age) + 31. It ages young dogs fast (a 1-year-old comes out around 31) and slows down later. It was built on one breed, so treat it as an estimate.
Life stage. The AAHA 2019 Canine Life Stage Guidelines use four stages: puppy (until rapid growth stops, around 6 to 9 months), young adult (until maturity, by about 3 to 4 years), mature adult, and senior, which is the last 25% of the dog's estimated lifespan.
Life expectancy. For each breed we use the life expectancy range on its American Kennel Club breed page. Senior age here is 75% of the middle of that range.
The old "multiply by seven" rule is not used here because the research above shows dogs do not age at a steady rate.
Sources
- Wang et al., Cell Systems (2020), as reported by Sci.News. Checked October 25, 2026.
- AAHA, 2019 Canine Life Stage Guidelines: life stage definitions. Checked October 25, 2026.
- American Kennel Club breed pages (weights and life expectancy as compiled in the open akcdata dataset). Checked October 25, 2026.
Frequently asked questions
How many dog years is 1 human year?
There is no fixed ratio. With the 2020 UCSD formula, a 1-year-old dog compares to a person of about 31, and aging slows after that.
When is a dog a senior?
The AAHA guidelines call the last 25% of a dog's estimated lifespan the senior stage, so it depends on the breed. Pick yours in the calculator to see the age.