Dog Age Calculator
Work out your dog's age in human years — based on an updated, scientific formula, not the outdated "multiply by 7" rule.
How to use the dog age calculator
- Enter your dog's actual age in years.
- The equivalent age in "human years" updates automatically.
Why is "multiply by 7" wrong?
The old rule of thumb (dog age × 7) assumes dogs age at a steady rate throughout their whole life — that's not true. Dogs age very rapidly in their first year (a 1-year-old is already roughly equivalent to 31 human years) and considerably slower after that.
This calculator instead uses the formula human age = 16 × ln(dog age) + 31, taken from a 2020 study from the University of California San Diego that compared epigenetic aging patterns (DNA methylation) in dogs and humans. The formula produces a well-known, often-cited result: an 8-year-old dog is roughly equivalent to 64 human years.
Frequently asked questions
Where does the formula come from?
From a study published in the journal Cell Systems in 2020 (Wang et al.), which compared chemical changes in DNA (methylation) in dogs and humans over time to find a more precise aging relationship than the traditional "×7" rule.
Why is a 1-year-old dog already equivalent to 31 human years?
Because dogs develop and mature very rapidly in their first year of life compared to humans — a 1-year-old is already sexually mature and nearly full-grown physically, which corresponds to late adolescence/early adulthood in humans.
Does the formula apply equally to all dog breeds?
The study the formula is based on used Labrador Retrievers. Smaller breeds generally age more slowly and live longer, while larger breeds often age faster — so the number should be treated as a general estimate, not an exact answer for every breed.