Stop multiplying by 7: how old is your dog in human years?

“How old is my dog in human years?” that’s probably one of the most frequently asked questions in the dog world as most of us want to extend our best friend’s life as much as possible, yet the answer remains uncertain. 

But determining our dog’s age is extremely important as it helps us adjust their healthcare, training, and lifestyle according to their life-stage.  If you are a dog owner or even a dog person, you might be familiar with the theory that somebody, at some point of history created: ‘1 dog year is equal to 7 human years.’ 

At the time, this made sense as the estimated life span of humans was about 70 years, while the life expectancy of an average size dog was 10 years.  Well, that theory is now part of the past.  Researchers from the University of California dismissed this rule due to the fact that science has increased the life expectancy of both dogs and humans, and not all dogs are ‘average size’.  So, they developed a new and improved formula to keep track of your dog’s age.

How old is my dog?

Here comes the tricky part.  To fully understand the age of our dogs, we have to bear in mind a few things:

  • Dogs and people are a very different species (and you probably already knew this!), so we have to erase from our minds the concept of making dog and human years equivalent. 
  • All dogs age at a different pace according to their breed as large size animals tend to have a shorter lifespan than smaller ones so the life expectancy of dogs can vary greatly.
  • A dog’s nutrition and their associated weight is likely the most important factor in aging.  In fact, after evaluating more than 50,000 dogs across 12 different breeds, a recent study revealed that overweight dogs will most likely live 2.5 years less than those with a healthy weight.


Based on the American Animal Hospital Association Canine Life Stages Guidelines, today’s vets divide dogs into six categories: puppy, junior, adult, mature, senior and geriatric. 

Life stages are a more practical way to think about the age of a dog than assigning a single number; even human health recommendations are based on developmental stages rather than exactly how old.  Just like a typical human toddler doesn’t need a colonoscopy, an average puppy doesn’t need its thyroid levels checked.

How to calculate dog years

Scientists have developed a more accurate way of estimating your life’s companion age. But stick with me because it’s no piece of cake: dogs have methylation marks on their DNA that indicate aging (pretty much the same as human wrinkles), which allowed scientists to come up with a brand-new formula to calculate their potential human age.

The formula looks like this, you multiple the natural logarithm of your dog’s age by 16, and then add 31 [16In (dog age) + 31 = human age], e.g., if your dog is 4, his human age would be 53.2.   And because we love to make it easy for you to calculate your dog’s age, we’ve put together a simple chart of your dog’s age in human years.

What about their energy?

Thanks to this new formula, we can easily estimate that the first couple years of a dog are equivalent to 40 years of a human. However, if you compare the energy of a 2-year-old dog to a 40-year-old person, the dog will probably win the race, literally.

Why? Simple, dogs burn all their energy really fast.  That’s why they always look so eager to go for a walk; unlike humans, who have a lot of stocked energy but release it slowly.  So, if we compare dogs and humans in a slow-paced walk, instead of in a speed race, humans would be capable of lasting much longer due to our resistance. This also explains why dogs need to sleep 13-14 hours a day, while we humans can easily make it with only 7-8 hours.

But no matter how energetic and healthy our dogs are, odds are that they will live a much shorter life than we will and that’s why it’s so important to enjoy each and every day of their lives by giving them all the love and care that they deserve!

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