Dog Age in Human Years Calculator (Science-Based, Not Times Seven)
By the Pets Locally team
Updated 2026
The old "multiply by seven" rule is wrong: dogs age fast in their first two years, then slow down. This calculator uses the published epigenetic ageing formula from a 2019 study, then adjusts for breed size, because small dogs live longer and reach old age later than giant breeds.
Convert your dog's age to human years
In years. Use a decimal for months, eg 0.5 for six months.
Bigger dogs age faster in later life.
The core formula comes from a 2019 epigenetic clock study of Labrador Retrievers: human age is roughly 16 times the natural log of the dog's age, plus 31. It is most accurate from about one year old. We blend this with a size adjustment for older dogs, since a Chihuahua and a Great Dane do not age at the same pace once past puppyhood.
Looking for someone local?
Search your town to find checked groomers, walkers, sitters and pet shops near you, with real owner reviews.
Find local pet services
