DogYearsHuman years to dog years
The reverse question: if a person is a certain age, how old is that in dog terms? Pick a human age and a dog size — we run the veterinary size chart backwards.
So a 40-year-old human is at roughly the same life stage as a five-year-old medium dog. Reverse conversion uses the same size chart, inverted — expect an estimate, not an exact birthday.
How the inversion works. The size chart maps dog years to human years in three segments: up to 15 in year one, up to 24 by year two, then a steady 4–7 per year by size. Reversing it is simple arithmetic on whichever segment the human age falls into. A human age of 60, for instance, lands at about 11 dog years for a small breed but only about 7.1 for a giant breed, because giant dogs pack more human years into each of theirs.
Going the normal direction instead? Use the dog age calculator.