Convert a dog's age to human equivalent years using size-adjusted rates.
Dogs mature rapidly in their first two years, then age at a rate that increases with body size. Giant breeds age nearly half again as fast as small breeds after maturity, which is why lifespans differ so much. The old multiply-by-seven rule badly misstates both ends: a one-year-old dog is far more developed than a seven-year-old child, and a large breed ages faster than the rule suggests.
Dog Age
First two years count about 10.5 human years each, then a size-dependent rate applies
First two years count about 10.5 human years each, then a size-dependent rate applies Dogs mature rapidly in their first two years, then age at a rate that increases with body size. Giant breeds age nearly half again as fast as small breeds after maturity, which is why lifespans differ so much.
The old multiply-by-seven rule badly misstates both ends: a one-year-old dog is far more developed than a seven-year-old child, and a large breed ages faster than the rule suggests.
This calculator takes 2 inputs: Dog's 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.