The old-age conversion standard for dogs used to be “one year of dog life equals seven years of human life.” But in reality, dog to human age conversion is not a standard case of “one size fits all.”
It applies to both the overall size of the dog affecting its lifespan and its life stage. Dogs age faster in their first couple of years of life, and bigger breeds of dog age more quickly than their smaller counterparts. Below is a list of a variety of breeds put together by Dr. Kelly M. Cassidy, and their average life expectancies. Below is a chart published by the American Kennel Club that lists dog age conversions based on their adult weight.