Quick: how old is your dog in human years?
You probably just multiplied their age by 7, right? So a 4-year-old dog would be 28? It seems like everyone who owns a dog knows this "1 and 7" rule for figuring out their dog's real age, but it's actually not true!
So why does everyone use this rule? For a long time, people have tried to figure out a "rule" for dog years and human years. In the 1950s, humans normally lived to age 70, and most dogs lived for about 10 years, so veterinarians probably decided on this "rule" by mistake.
In fact, your dog's age depends on lots of things including their breed, but there's still a pretty easy way to find out your dog's age.
A French researcher calculated that all dogs age about 15 to 20 times faster than people until their first birthday, then they slow down. For the most part, the older your dog is, the faster it grows up.
You can use this handy chart to tell your dog's age. Dogs under 20 pounds are small, between 21 and 50 are medium, from 50 to 90 are large, and any dogs above that are giant. As you can see, a 10-year-old small dog is only 56, while a 10-year-old giant is 78.
If you're looking for a dog that will stay with you for a long time, pick a toy poodle, mini daschund or cairn terrier, they all usually last 13 years or more. Bulldogs, on the other hand, have an average lifespan of just 6 years.