Convert a dog's age into human years with a breed-size adjustment.
A common estimate of dog age in human years is sixteen times the natural logarithm of the dog's age plus thirty-one. Breed size scales the result because larger breeds tend to age faster in human-equivalent terms. The old one-year-equals-seven rule is inaccurate for most of a dog's life. The logarithmic curve better captures the rapid aging of puppies and the slower aging of adults.
Dog Age in Human Years
Human years = 16 x ln(dog age) + 31, scaled by breed size
Human years = 16 x ln(dog age) + 31, scaled by breed size A common estimate of dog age in human years is sixteen times the natural logarithm of the dog's age plus thirty-one. Breed size scales the result because larger breeds tend to age faster in human-equivalent terms.
The old one-year-equals-seven rule is inaccurate for most of a dog's life. The logarithmic curve better captures the rapid aging of puppies and the slower aging of adults.
This calculator takes 2 inputs: Dog age, Breed size. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.