Cat Age Calculator – Convert Cat Years to Human Years

Enter your cat’s age in years to calculate their age equivalent to human years.

How to Calculate a Cat’s Age

Cats physiologically age much more quickly than people do, and so their equivalent age in human years is a bit older than in cat years. Cats age the most in their first two years of life, where a cat will reach the equivalent of 15 human years in their first year and 24 human years in their second.[1]

After their second year, a cat will age the equivalent of four human years each year.

kittens age much more quickly than a human, especially in their first two years

Cat Age Formula

So, unlike finding your own age, to find the age of a cat in human years you’ll need to use the following formula:

If the cat is one year old, then their age is equivalent to 15 human years.

If the cat is two years old, then their age is equivalent to 24 human years.

If the cat is older than two years old, then use the following formula to estimate their age:

equivalent human age = ((cat’s age – 2) × 4) + 24

Thus a cat’s equivalent age in human years is equal to their age minus two, times four, plus twenty-four.

How Long do Cats Live?

Cats all age differently and lifespan varies by breed, health, and whether the cat lives indoors or outdoors. The average lifespan of a cat is 12-14 years, but cats can easily live into their late teens to even early twenties.[2]

How to Estimate a Cat’s Age

If you adopted a kitten or cat and aren’t sure how old they are, then the best place to start when estimating age is their teeth. Teeth are a strong indicator of age, especially in younger cats.[3]

3-6 weeks: baby teeth come in

3-6 months: baby teeth fall out, and adult teeth are in

1-2 years: teeth are clean and sharp

3-5 years: teeth are starting to wear and are yellowing

More accurate assessments can be performed by a veterinarian, and often they will look at other factors such as the coat, muscle definition, and other health indicators to judge the cat’s age.

Want to find the age of a dog in dog years? Try our dog age calculator.


  1. Catster, How to Calculate Cat Years to Human Years,
  2. International Cat Care, How to tell your cat’s age in human years,
  3. Helen Anne Travis, Cat Years To Human Years: How Old Is My Cat?, PetMD,