When it comes to how old we imagine our dogs to be in human years, most of us use a calculation that says dogs age seven years for every one human year.

So a 1-year-old dog is roughly the same, developmentally, as a 7-year-old human. A 2-year-old dog is equivalent to a young teenager, et cetera.

But a new study by researchers at the University of California San Diego School of Medicine along with other scientists across the country is casting doubt on that math, according to a story by USA Today.

The researchers found that not only is the 1:7 ratio of dog to human years is off, it’s off by a lot.

The study was conducted on 104 Labrador retrievers up to 16 years old. According to its findings, a 1-year-old dog more closely pairs up to a 30-year-old human instead of a 7-year-old child.

“This makes sense when you think about it — after all, a nine-month-old dog can have puppies, so we already knew that the 1:7 ratio wasn’t an accurate measure of age,” said the study’s senior co-author Trey Ideker, professor at UC San Diego School of Medicine and Moores Cancer Center, in a UC San Diego news release.

The research, published July 2 in Cell Systems, is the first that is transferrable across species, and offers veterinarians a tool “for evaluating anti-aging interventions”.

“There are a lot of anti-aging products out there these days — with wildly varying degrees of scientific support,” said Ideker, “But how do you know if a product will truly extend your life without waiting 40 years or so? What if you could instead measure your age-associated methylation patterns before, during and after the intervention to see if it’s doing anything?”

Methylation patterns refer to the formula used to calculate a dog’s age compared to human years. The formula is based on the changing patterns of chemical tags in dogs and humans as they age.

The study found that while dogs age rapidly in their early years, when a dog reaches a certain age the aging process slows.

“A 1-year-old dog is similar to a 30-year-old human. A 4-year-old dog is similar to a 52-year-old human. Then by seven years old, dog aging slows.”

The study was done only on Labrador retrievers, and researchers pointed out that dog breeds can age at different rates.

To calculate your dog’s approximate age, you can use the Google calculator. Go to the calculator and enter 16. Then click the “ln” option to get the natural logarithm (or ln) function. Then input the dog’s age and hit equal (=). When you get that number, add 31 and you get the equivalent of the dog’s age in human years.

So a 7-year-old dog would be roughly 62.1 human years old.

Cox Media Group