How many years is 3 dog years? How many human years is
3 dog years?
Dogs age much faster than humans, so dogs are usually adults after 2 years.
It is not a straight linear relationship. Instead, a dog might age 15 human years
during its first year, and only about 4 human years/year after age two or three.
In general, big dogs have shorter life spans than smaller dogs.
Note that this is just an approximation.