How Old is 9 in Dog Years?

9 in dog years roughly equals 56 in human years.

This calculation was made for a medium-sized dog (21 to 50 pounds) using the recommendations from the AKC (American Kennel Club).

There are 2 ways of calculating the conversion from human years to dog years. The above result was calculated using the more correct way, we’ll explain what makes the other way incorrect later in this article.

The table below shows dog years and their equivalent to human years, with different columns for different sizes.

Dog's Age in YearsHuman Years (Small Dog)Human Years (Medium Dog)Human Years (Large Dog)

9 in dog years

Calculating how many human years is 9 in dog years

As mentioned above, there are 2 main ways of calculating dog years to human years and vice versa. There’s a correct way and an incorrect way.

The incorrect calculation

The majority of people still believe that one dog year equals 7 dog years. This assumption was probably first introduced in the 1950s, however this isn’t the best method of calculating it.

There has been a lot of research since then that disproves this ratio of 7 to 1, people continue to believe it. The formula could have been based on the assumption that dogs live to about 10 years old and humans up can live to 70, however we don’t know the date it was first introduced.

So while the 7 to 1 rule is simple to remember and calculate however, it’s sadly incorrect.

The correct formula

The correct way of converting human years into dog years is a bit more complex.

The American Veterinary Medical Association has the following to be said about it:

  • The beginning year of a medium-sized dog’s lifespan equals around 15 human years.
  • The second year in a dog’s lifespan equals about 9 human years.
  • From that point forward each human year is equal to the equivalent of four to five dog years.

Keep in mind that smaller dogs tend to live longer than bigger dogs. Scientists concluded that every 4.4 pounds of body mass reduced a dog’s life expectancy by about a month.


Becky Roberts

Becky Roberts

One of Becky's favourite things to do every morning is to browse the top pet-related forums, looking for issues and questions that people have. She then shortlists the most common ones, and turns them into blog posts for Fuzzy Rescue. She's had over 4 cats and 2 dogs over the past decade, so she does know a thing or 2 about raising/training, and more importantly, loving them. She's the only one on our team that doesn't like coffee, but it seems to us she really doesn't need more energy :). We're very fortunate to have her on board as she does most of the heavy listing for the site, outputting an insane amount of content each month. Read More

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