How Old is Your Dog? Understanding Dog Years

How Old is Your Dog? Understanding Dog Years


Many of us have heard the idea that one dog year is equal to seven human years. And it’s true that dogs do age much differently than people; a fact that anyone who has had to say goodbye to an older beloved furry friend will understand this only too well. 

Is it true, however, that it’s as simple as multiplying your dog’s age by seven to understand where they are in their life?

The idea of one to seven originally came from the idea that dogs on average live about ten years while humans on average live about seventy. While it’s math that makes logical sense there are a few problems with the simplicity of this equation. For example, people are starting to live longer, not all dog breeds have the same average lifespan, and dogs biologically mature into adults much more quickly than humans.


Puppy being held

Aging at a Different Pace

This idea that ‘dog years’ is more complicated than just multiplying by seven is not a new one. It was in 1997 that a team of veterinarians led by Gary Patronek sought to establish a better way to calculate dog ages, wanting to match their age in real years to how far they were in their life span compared to humans.

Understanding why dogs age differently doesn’t just vary between the whole of dogdom and us, there is a notable difference of lifespan between smaller and larger dogs.

Normally larger animals tend to live much longer than small ones. An African Bush Elephant can live sixty to seventy years while a mouse normally lives just one to two years. With dogs, though, that isn’t the case.

Evolutionary biologist Cornelia Kraus says that large dogs’ lives “seem to unwind in fast motion” from an article in Inside Science. Studies showed that for every 4.4 pounds heavier in mass a dog was, their life shortened by roughly a month.

The reason? No one, not even the researchers, seem to know. Kraus did put forth a couple ideas. It’s possible larger dogs are more prone to complications from certain illnesses. Additionally, the faster growth rate could lead to higher chances of abnormal cell growth leading to cancer.

Whatever the reason, researchers and scientists haven’t stopped trying to figure out why there is a difference at all. And Patronek’s team did indeed come up with a way of calculating doggie years much more accurately.


How Old is Your Dog?

The basic idea behind figuring out how old your furbaby is goes by the following:

  • The first year of a medium dog’s life equals about 15 human years
  • The second year equals about 9 years
  • Each year following equals about 5 years

Of course, these numbers vary by size. If you want to get a better idea for your own pup, take a peek at the chart below!

Dog age chart

There have been more studies in the years since then. In 2019 researchers from the University of California San Diego developed a new way to figure out a dog’s ‘people age’ based on changes in their DNA over a span of years. To do this, they multiplied the “natural logarithm” (or changes in the DNA) of your dog’s age by 16 then added 31.

Of course, the above study was done only on Labrador Retrievers so the result could be different for your own pooch based on breed and size. If you want to give it a try, though, there are online natural logarithm calculators that are easy to check out!


Why Do Dog Years Matter?

Why is it helpful or even important to understand how old your dog might be in human years? 

In the same way your own body might start to change what it needs at different stages of life, so does your dog’s. A puppy will need a different type of food, exercise, and stimulation than a dog who has reached its twilight years. 

Plus as a pet grows older, there are different concerns to keep an eye out for (such as sight or hearing loss). Understanding where they are in ‘doggie years’ can help to know when to be on the lookout. After all, they can’t tell us when something is wrong. 

It’s recommended that once a dog reaches seven years old, it’s a good idea to start visiting the vet twice a year and getting blood work done so you can be aware if any condition or disease related to age crops up, such as any cancers or diabetes.

It can also help you understand and connect with your pet better! Knowing where your pooch is in their life stage can help you know the best way to provide them with the things they need to live their happiest and healthiest life.

Puppy in a field

For more doggie photos and pup-related fun, follow us on Instagram at @joyrideharness. And for a more detailed blog post about finding the best size dog harness for your pup, check out this blog post!


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