How are Cat Years Calculated? – Cat to Human Age Chart

Calculating Cat Years to Human Years

I’m sure a lot of you often wonder about this question, “If my cat was a human, how old would she be?”. Below there will be a chart to compare your cat’s age to human age. But firstly you might want to know, how are cat years calculated? Cats (and dogs) have an earlier maturing age when put into comparison with humans. Which is why within the first few years of their life, their relative human age jumps up so quickly compared to their relative age later on in their lives. This is why we don’t just use a simple linear method of calculating their age (such as multiplying their age by 7 to get human years).  

Cat Age to Human Age Chart


Cat age – 0 = 0 – Human age

Cat age – 1 = 15 – Human age

Cat age – 2 = 24 – Human age

Cat age – 3 = 28  – Human age

Cat age – 4 = 32 – Human age

Cat age – 5 = 36 – Human age

Cat age – 6 = 40 – Human age

Cat age – 7 = 44  -Human age

Cat age – 8 = 48 – Human age

Cat age – 9 = 52 – Human age

Cat age – 10 = 56 – Human age

Cat age – 11 = 60 – Human age

Cat age –12 = 64 – Human age

Cat age – 13 = 68 – Human age

Cat age – 14 = 72 – Human age

Cat age – 15 = 74 – Human age

Cat age – 16 = 76 – Human age

Cat age – 17 = 78 – Human age

Cat age – 18 = 80 – Human age

Cat age – 19 = 82 – Human age

Cat age – 20 = 84 – Human age

Cat age – 21 = 86 – Human age

Cat age – 22 = 88 – Human age

Cat age – 23 = 90 – Human age

Cat age – 24 = 92 – Human age

The method this chart uses to calculate cat age was developed by Monsieur LeBeau.

How are cat years calculated? As you can see, between the cat ages 0 to 2 years, there is a quick jump up in the relative age between humans and cats. From the age of 2 years we then add 4 years on for each human year until we reach the cat age of 14 years. From then on we add on 2 years for each human year after.

This is a much more accurate method of calculating cat age than using a simple linear method.

Note that this method used is only an estimate comparing cat to human ages. For different breeds of cat, the numbers can vary. You can contact a vetinarian for a more accurate calculation for your pet.


Cat Age Indicators

For anyone who has acquired a cat either from a rescue home, or from stray and in either case has no way of knowing the age of their cat. There are indicators that you can use to get a rough indication to how old your cat is.

  • Cat’s teeth: The condition of a cats teeth is perhaps the main way to get an indicator of his/her age. Generally the older the cat is, the more the teeth of the cat will be stained.
    For a kitten, the first sets of teeth will make an appearance between 2 to 4 weeks old. At around 4 months old you will see their more permanent set of teeth come in.
    A bright set of white permanent teeth can indicat a cat to be around 1 year old, more staining can occur a year or so after, and around 3 to 5 years you may see a tartar build-up. Teeth in poor condition or missing teeth can indicate that the cat may be more of a senior age.
  • Cat’s coat: Generally speaking a cat’s coat will grow to be thicker and more coarse as the cat gets older. Young cats will have finer and softer fur than older cats. In senior cats you may see some greying, patches of white, and the fur may generally look more tatty.
  • Cat’s eyes: It isn’t as easy to define a cat’s age by looking at their eyes when a cat is younger than the age of 12. Cats older than 12 can develop some cloudiness in their eyes and if you look closely at an older cat’s iris, it may look more jagged and not as smooth as a young cat.
    Many senior cats will also develop sight loss too, and may have watery looking eyes or discharge.
  • Cat’s body and muscle tone: Older cats tend to lose their muslcle tone as they get older. Younger cats generally will have a more defined and healthy looking tone. As a cat gets into the later senior years, they can begin to look bony and thinner with their skin seeming to hang a little looser.