For many years human beings have always taken one dog year and converted it into seven human years. This theory has been adjusted over the years because science doesn’t back this 1 dog year is equal to 7 human years concept.
Apparently how old your dog is in human years will depend on a variety of variables. A study in 2019 revealed that different breeds and different sized dog’s age at different levels. For example, you may find that smaller dog breeds live longer whereas your big Newfoundland may live a shorter life.

This study focuses on the changes that have occurred to the dog’s DNA over the years. While you could convert your dog’s one year into seven human years, this will be an estimated conversion based on this 2019 study. While we’re not quite sure where the 1 to 7 ratio started, it’s something that many humans aren’t willing to give up.
One guess about the concept of 1 dog year equaling 7 human years is that in the old days most human beings lived to be 70 years old and most domesticated dogs lived approximately 10 years. While we have no factual content to back this theory up, it’s a relatively accepted concept.
So, how does one know how old their dog is in human years?
Well, that’s what we going to help you find out today.

The American Veterinary Medical Associates has created a formula to help you figured out how old your dog is in human years:
- 15 years of your life is equivalent to the first year of a medium-sized dog’s life.
- The second year of your medium-sized dog’s life is equivalent to 9 human years.
- After this second year of life, your medium-size dog’s conversion to human years is approximately 5 years for every 1 year in human beings.
This means that during your pet dog’s first year, they’ve aged 15 years when compared to human growth. Now, your dog is 2 years old, so you’d take 15 human years for his first year on Earth and add 9 human years for your medium-sized dog’s second year of life. This means that your two-year-old dog is approximately 24 years old in human years.

We’re not quite sure how realistic this theory is, but it’s something that the American Veterinary Medical Associates is starting to abide by. We’re sure you’ll still calculate your dog’s human years based on the one to seven-year ratio, but we wanted to share this new theory that was released in 2019 to help you better understand how your dog ages when compared to everyday human beings growth patterns.