This Chart Will Tell You Exactly How Old Your Dog Is in Human Years

We've all heard the old rule of thumb that one dog year equals seven human years. But in reality, the situation is more complicated. Small dogs live much longer than larger breeds, making this old saying only approximately true. Is there a more accurate way to understand the life stage of your dog?

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The New Rules of Dog Years

Yes, answers Jesse Grady, a clinical instructor of veterinary medicine at Mississippi State University, in a recent article on The Conversation that is basically the answer to every obsessive dog parent's prayers. In the piece, Grady explains exactly what's wrong with the usual way of calculating the life stage of our pets and offers a more scientifically accurate replacement.

"There's a bit of logic behind" the old one-dog-year-equals-seven-human-years rule, admits Grady in the article. "People observed that with optimal healthcare, an average-sized, medium dog would, on average, live one-seventh as long as its human owner."

But, he goes on to note, "not every dog is 'average-sized'... think a Chihuahua versus a Great Dane." What both anxious pet owners and veterinarians need is a way to take a specific dog's size into account when calculating life expectancy. Handily, the doggie doctors have developed just such a tool in the form of the chart below.

The Conversation

Every Dog Is Different

Simply by assessing your dog's size and following the corresponding line, you can figure out if your fur baby is the equivalent of an active 50-something or an aged 80-year-old. (Cat lovers can click through to Grady's original post for a corresponding chart for their feline friends.) But, Grady cautions, just like humans, dogs can age more or less quickly based on lifestyle factors. Fifty feels a lot different if the only exercise you do is opening the door at McDonald's than if you've been running marathons and eating quinoa for decades. The equivalent is true for fitter and fatter dogs too.

For this reason, the most accurate assessment of your pet's life stage will come from a professional who can assess the overall health of the animal. "As is the case for people, your pet's overall health status can influence their 'real age' for better or for worse. So next time you take your pet to the veterinarian, talk about your animal's life stage and find out what health recommendations come with it," Grady recommends.

In the meantime, the chart above will give you a much more precise sense of how many more years you'll get to spend with Spot or Rex than the old, outdated seven-year rule.