After the first two years—boy, cats develop quickly—the conversion from cat years to human years is pretty easy. So we made a chart to show you the real way to calculate it.

Cat owners across the country are known for treating their cats just like their human offspring, so it's natural to complete the process by figuring out how old our cats are in human years. 

Luckily, it's pretty easy to do, says Marty Becker, DVM and founder of Fear Free Pets. But if math isn't your thing, feel free to simply scroll down to the handy-dandy chart below. We won't mind!   

How to Calculate Your Cat's Age in Human Years

At first it's a little tricky, but then it gets very simple, Becker says. That's because cats will develop rapidly in their first two years of their lives—reaching the human equivalent of the mid-20s by the time they're 2 years old. (Who else wishes we could zoom through puberty that fast? It can't just be me.) 

Here's how Becker lays out the process: A 1-year-old cat is the equivalent of a 15-year-old human. Then, a 2-year-old cat is 25 in human years. Then it gets much easier: Each year of a cat's life is roughly equal to four human years, so a 3-year-old cat is about 29; a 4-year-old cat is 33; a 5-year-old cat is 37; and a 6-year-old cat is 41. And so on and so on. If your cat gets to 20, she's around 97 human years old.

Unlike dogs—who have different human age equivalents depending on their size—the formula for cats is universal because they're all roughly the same size.

To find out the exact human age of your cat, look at the chart below!

Cat Age Calculator Chart

Chart showing different cat ages with coinciding human years equivalent
Credit: Rebecca Hart

When Is a Cat No Longer Considered a Kitten?

Your kitten will develop so much in her first year it's actually a little crazy. 

"The first year is the terrible twos and the teenage years in one year," Becker says. 

Oof. That's why it's probably a good idea to consult this guide on how to care for your kitten. Then, you'll want to make sure you have all the essentials.  

When Is a Cat Considered a Teenager?

Probably whenever she stops really listening to you, avoids her chores, and starts spending too much time staring at her phone. In reality, this occurs shortly before your cat turns 1 and lasts a few months after her first birthday.

By that time, she'll be a young adult cat. 

Illustration of three different cats at different ages
Credit: Rebecca Hart

How Old Is an Adult Cat?

By our human standards, cats are considered young adults basically when they turn 1. At that point, they'll have finished their physical development and are waiting for their minds to catch up, Becker says.

"They've got their younger, physical maturity. Their mental maturity is not there," he says. 

That will arrive as they end their second years on earth and move firmly into the adult phase.

When Is a Cat Considered a Senior?

Cats become seniors around their 11th birthdays, when their human age creeps up into the 60s. That's when they'll start considering retirement from their extremely strenuous professional lives.

How Many Years Do Cats Live on Average?

It's common to see a cat reach 20 years old (almost 100 in human years!) these days, Becker says, so it's safe to assume a healthy cat will make it within a few years of that. Recently, the world's oldest a cat made it all the way to 31 years old

We can't guarantee your feline pal will make it into a third decade, but there are a few things you can do to elongate your cat's life. Becker lists three main factors that determine your cat's longevity: heredity, environment, and nutrition.

There's not much you can do about heredity once you bring home your cat, Becker says. But you can do your best to make her environment safe. That means limiting time outside—where dangers like predators, vehicles, and parasites could injure your cat. That's why outdoor cats generally don't live as long as their indoor counterparts. 

The third factor is nutrition, so you'll want to work with your veterinarian to make sure your kitty stays as close to her healthy weight as possible. Cats at or near their ideal body weight will live longer than those who aren't, Becker says.