Everybody knows that one dog year is supposed to be equal to about seven human years. All you have to do to figure out your dog's "human" age is to multiply his current age by seven. But what about cat years? How are those calculated?

Don't worry—we've got the answers to your questions here.

Are cat years anything like dog years?

Not really. Cat years can't be simply multiplied by a specific number like dog years can, because cats mature quickly and then live a longer adult life than most dogs do. Their age in "human years" jumps significantly in the first two years of life and then slows down.

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What is the conversion rate between cat and human years?

There's no scientific way to tell exactly what the relationship is between cat years and human years, but most experts agree that the first year of a cat's life is equal to about 15 human years, and the second year of life is another nine or 10. After the first two years, each additional year is about four human years.

How do I calculate my cat's age in human years?

So to calculate your cat's age, add 15 years for the first year plus nine for the second year. Then add another four for each additional year that your cat is old.

For a cat that is over two years old, the equation might look like this:

4(X-2) + 24

(where X is your cat's age)

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How old is my cat in human years?

If you don't want to do the math (we don't blame you), here's a handy chart for determining your cat's human age.

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What if I don't know how old my cat is?

Of course, in order to figure out your cat's so-called "human age," you have to know how old they are to start with. We've got you covered.

Indoor cats typically live about 12 to 18 years, but they can occasionally live into their 30s. If you're unsure of your cat's age for whatever reason, there are some physical signs you can look for.

Your cat's teeth will be larger permanent teeth (rather than kitten teeth) if it's about one year of age or older. After that, a cat's teeth will become yellowed over time, just like human teeth, so the yellower the teeth, the older the cat. Cats with a little bit of yellowing on their teeth may be one to two years old, while those with a buildup of tartar on their teeth are more likely to be three to five years of age. If your cat is missing teeth, it's probably getting up there in age.

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Younger cats also usually have shinier coats and more muscle definition than senior cats. You can guess the age of your cat by how well you can feel their protruding bones and how thick and coarse their fur has gotten over time.

Lastly, younger cats have brighter eyes, smoother irises, and fewer issues with eye discharge. If there's some cloudiness to your cat's eyes, he or she is likely over the age of 12.