Skip to Primary Content

Sunset Veterinary Clinic

Ask the Vet: Are Seven Dog Years Equal to One Human Year?

A Brown Dog Lying on Grass Next to a Plant Pot Outside

How old is your dog?

The old adage is that, for every one human year, a dog ages seven years. So, is this true?

Below, we learn how veterinarians determine the most accurate age of a dog in relation to human years — as well as what factors contribute to canine aging the most.

Determining a Dog’s Age in Human Years

Can you really just multiply a dog’s age by 7 to get their relative age in human years?

Not exactly. The truth is it’s a bit more complicated than that. 

In fact, there’s a new formula that is much more accurate (though it’s still not perfect):

For any dog older than one, you multiply the number 16 by the natural logarithm of the dog’s age, and then, you add 31. 

If calculating natural logarithms isn’t your strong suit, you can also find a quick dog age calculator here.

What do veterinarians look at to determine a dog’s age?

When we encounter a dog we’ve never seen before — for example, a stray or newly adopted dog — these are the things we look at to determine their age:

  • Breed size (Small, medium, or large breed?)

  • Teeth (Do they have puppy teeth? If they have adult teeth, how worn are they?)

  • Graying hair (Gray on the muzzle is a sign of aging.)

  • Eyes (Lenticular sclerosis in the eyes causes a grayish haze on the lens and is another sign of aging.)

  • Signs of arthritis (Do they move more slowly or have trouble walking?)

What are the major causes of rapid aging in dogs?

Unfortunately, there is not an always-reliable methodology or resource available that can predict the age of our canine patients.

What we do know is larger breed dogs tend to age at a faster growth rate than small breed dogs. Still, the reasons why have yet to be discovered. Further studies need to be performed to determine the mechanisms behind growth rates and mortality. 

Fortunately, research is ongoing in this area. For example, Texas A&M University and the University of Washington have teamed up to carry out a study that will examine 10,000 dogs over the course of 10 years. Called The Dog Aging Projectthis study will evaluate what environmental and biomedical factors contribute to the aging of our pets. Hopefully, the results will help vets and parents alike give better dog care to their pets.

Promote Dog Health: Help Your Pet Live a Long, Healthy Life

Studies show that dogs who regularly visit the vet for yearly checkups and regular dog vaccinations live longer than dogs who rarely go to the vet. To keep your pup happy and healthy for years to come, don’t forget to schedule their annual visit at Sunset Veterinary Clinic today!