Calculating the "human" age of your pet is easy, right? Just take their actual age times 7 and you have it! Not so fast, according to WebVet.com.  Apparently, the old "times 7" isn't quite accurate!

FOR DOGS

Dogs age a lot faster during their first two years than they do the rest of their lives.  The speed of aging varies by breed; large dogs are considered "senior" by 5, medium and small-size dogs reach that designation by 7 and 10 years, respectively.

Veterinarians say to assume that a one-year-old dog equals a 12 year old human and a 2 year old equals a 24 year old human.  For every year after, just add 4.

Here's a chart, courtesy of PetsAdviser.com.

FOR CATS

Cats age a little faster than dogs do in their first year, so a one-year-old cat equals at 15 year old human.  But by 2-years old, cats and dogs age at approximately the same "4 years for every human year" rate.

Another chart, again courtesy of PetsAdviser.com.