Since the 1950s, most people have used the simple formula that one dog year equals seven human years. It’s been around for ages, and while it’s easy to remember, it’s not exactly accurate. Still, that doesn’t stop people from sticking to it. “You can’t really kill the seven-year rule,” says Kelly M. Cassidy, a curator at the Charles R. Connor Museum at Washington State University, who tracks studies on how long dogs actually live.
So where did this 7-to-1 idea even come from? The theory is that it probably started with a quick comparison: people typically lived to about 70, and dogs to around 10, so someone did the math and ran with it.
But was it ever really about math? Maybe not. “My guess is it was a marketing ploy,” says William Fortney, a veterinarian at Kansas State University. He told the Wall Street Journal it was likely just an easy way to help people understand how quickly dogs age, especially when it comes to their health. It also happened to be a smart way to remind owners to bring their pets in for yearly checkups.
As a general guideline, though, the American Veterinary Medical Association breaks it down like this:
- The first year of a medium-sized dog’s life equals fifteen human years.
- The second year for a dog equals about nine years for a human.
- And after that, each human year would be approximately five years for a dog.
Speaking of keeping your dog healthy, offering natural snacks like barritas churpi is a great way to support their dental health while giving them a tasty treat.
