Dog Age Calculator
Convert your dog's age to human years.
57 human years
Life stage
adult
Typical lifespan
13 years
Years remaining (avg)
~8.0
Uses the formula 16 × ln(dog_age) + 31 from a 2019 UC San Diego study, with size adjustments. The 1:7 dog-years rule is a myth. Dogs age much faster early in life and slower later.
About
The 7-to-1 rule has been wrong for decades. A 2019 UC San Diego study found that dogs age much faster early in life and slow down later, following a logarithmic curve. The formula is human_age = 16 × ln(dog_age) + 31. This calculator uses that and adjusts for breed size.
How to use
- Enter your dog's age in years (decimals are fine for puppies).
- Pick the size category: small, medium, large, or giant.
- See the human-equivalent age.
FAQ
Why is the 7-to-1 rule wrong?+
Dogs reach reproductive maturity within their first year, which is the equivalent of a human teenager. After that, aging slows. A flat 7x multiplier overstates the gap for puppies and understates it for senior dogs.
Where does the formula come from?+
A 2019 study from the UC San Diego School of Medicine compared methylation patterns in dog and human DNA and found a logarithmic relationship. The proposed formula is human_age = 16 × ln(dog_age) + 31.
How does size change the result?+
Smaller dogs live longer (often 14 to 16 years). Giants live shorter (often 7 to 10). A small multiplier reflects that. A 10-year-old Great Dane is biologically older than a 10-year-old Chihuahua.