This result is an estimate only. Check with your bank or the relevant authority before making decisions.
How it is calculated
Human age = 16 × ln(dog age in years) + 31
ln is the natural logarithm, so the human age rises quickly in a dog’s first years and slowly afterwards
The old rule, dog age × 7, is shown only for comparison
The formula comes from a 2020 UC San Diego study that compared DNA methylation in 104 Labrador Retrievers with 320 humans. For cats, use the cat age calculator.
Worked example
A 5-year-old dog:
ln(5) = 1.609
16 × 1.609 + 31 = 56.8 human years
The old rule would say 5 × 7 = 35
Why your number may differ
The formula was fitted to Labrador Retrievers and is not exact for every breed. It gives very low values for puppies under a few months, so the calculator starts at 3 months. A dog’s real health, life stage and expected lifespan depend on breed, size and care. This is not veterinary advice.
Frequently asked questions
How is dog age converted to human years?
This calculator uses human age = 16 × ln(dog age) + 31, from a 2020 study of Labrador Retrievers that compared how DNA changes with age in dogs and humans. A 1-year-old dog comes out at about 31 human years.
Why not just multiply by 7?
The ×7 rule is a rough guide. Dogs mature much faster in their first years and then age more slowly, so a 1-year-old dog is closer to a young adult than a 7-year-old child.
Does the breed or size matter?
Yes. The formula comes from Labrador Retrievers, and large breeds tend to have shorter lives than small breeds. Treat the result as a guide, and ask your vet about your dog’s health and life stage.