How old is my cat in human years? Probably older than you think.

We've all had that one animal we love so much we almost view them as a child rather than a pet (probably because they're smaller than us, unless they're a horse). But what if we told you there is a chance your furry friend could be older than you?

Flossie is a 27-year-old British tortoiseshell cat − and the oldest living cat. Though 27 doesn't seem to be that old, Flossie is actually about 120 human years old.

Aging in cats is different from aging in humans, and while you may think your cat is a certain age based on how long you have had them, they're probably older than you realize.

Continue reading to learn how old your cat is in human years and the factors that can determine a cat's life span. 

How many cat years are in a human year?

As crazy as it may seem, the first year of a cat's life is equivalent to 15 years of human life, according to Purina. So when your kitten has its first birthday, it's old enough to get its driver's permit if it were human. 

In their second year, cats age another nine human years, making them 24 human years old on their second birthday. Every year after that adds four years, Purina reports. 

Cat years to human years

If you got your little companion 10 years ago, it's 56 human years old. How old is your cat? 

If your cat is older than 21, add four years for every additional year to find out his or her current age.

How long do cats live?

The average life span of a cat is 13 to 17 human years, and 20 years is pretty dang old, according to PetMD. A cat's life span will vary based on nutrition, lifestyle, preventative measures, breed and genetics. 

Indoor cats typically live much longer than outdoor cats because they are sheltered from harsh weather, parasites, predators and vehicles. 

If you are unsure of your cat's age, take your pet to a local veterinary clinic for a more specific answer.

Can cats smile?Yes, but not in the way you'd expect

Just Curious for more?

Here at Just Curious, we're looking into all of your questions. From "What are healthy snacks?" to who the youngest Kardashian is to more information about cats and why they knead, make sure to check out USA TODAY's Just Curious section for more trivia, tidbits and information you might want to know.