Cat Years – How Old is my Cat in Human Years

There are a lot of speculations when it comes to calculating the relationship between cat and human years. Like dogs, there’s a common misconception that a 1-year-old kitten is as old as a 7-year-old child.

However, there are no reliable scientific studies to back it up and the computation isn’t as simple as some people might think

How Do Cats Age Compare to Humans?

Kittens undergo development remarkably much faster than humans. As for the 1-year to 7-year ratio, the calculation is much more complicated than it may seem. So to make the formula a little less complicated, let’s assume the average domestic cat’s stages of development.

  • Early Development

Domestic cats only go through a gestation period of 58 – 67 days. They then give birth to kittens that require only 10 – 12 weeks of attention and care. After that, kittens can then be separated from their mothers as they’ve passed their “toddler years” at this stage.

That is why some foster homes wouldn’t let their kittens to be adopted unless they are at least 10-weeks-old. Therefore, kittens which are around 3 – 6 months should be equally developed as a child around 4 – 8 years of age.

  • Cat Puberty

Unspayed female cats or queens start menstruating or come into heat as early as 4 – 6 months. At this stage, they are considered able enough to get pregnant; where 8 – 10 months are the healthiest times for them to have a litter.

On the other hand, male cats, or tomcats, are able to impregnate once they reach 6-months-old, and some can be fathers to litters as early as 10-months-old.

In comparison, an average female child reaches puberty as early as 9-years-old to as late as 15-years-old, while boys reach sexual maturity between 12 and 14 years of age.

  • Maturity and Old Age

On the average, cats that have reached the age of 10 – 12 years are considered senior cat-izens. They show signs of aging the same way humans do like developing eye and knee problems.

But not everything is noticeable to the naked eye. Their internal organs may deteriorate over time like developing certain cancers; while some develop high-blood pressure and heart problems which are something you can only detect with the help of a vet.

However, this doesn’t mean that all cats are old when they reach these ages. Some cats may show signs of aging earlier than others while some will stay practically healthy until after they reach the age of 12.


The Indoor and the Outdoor Cat

Generally speaking, the average lifespan of a domestic cat sits between the range of 13 and 17 years, with the average single value of 15 years. However, not all cats share the same fate of living a long, full life due to some reasons that affect the way they age. To sum it all up, it all goes down to one determining factor: whether they are an indoor or an outdoor cat.

  • Indoor Cats

Indoor cats, as the name implies, are cats that spend most of their lives inside the safety of their humans’ homes. They tend to live longer as they’re being provided with health and general necessities and protected from dangers of the outside world.

Because of the conditions they are in, indoor cats’ have a longer life expectancy that goes between 15 and 20 years, where 18 years is the general average. However, some reports suggest that some indoor cats live to more than 20 years!

  • Outdoor Cats

Those cats you see outside that are the feral, strays or those let out by their owners are outdoor cats.

Unlike indoor cats, outdoor cats are more prone to health issues and the dangers of the outside world. Their life expectancy is lower than their indoor cat counterparts ranging only around 3 – 10 years and those that reach the age of 10 are considered to be the lucky ones.

ageing cat

Cat Year Calculator

When it comes to development, a 1-year-old kitten should be the same age as a 15-year-old human and at 2, they are equally physically mature as a 25-year-old human. Then, they tend to age slower every year after two until they reach old age.

They age equivalent to four human years for every year after 2-years. So that means that a 5-year-old cat should be the same age as a 37-year-old human.

To give a better perspective on how cat years relate to human years, let’s take a look at the calculations on our cat year table.

Indoor CatsOutdoor Cats







However, we are only talking about averages here so the calculations shouldn’t apply to every cat and take everything with a grain of salt. Nowadays, due to medical advancements and healthier cat food formulas, most indoor cats tend to live past 20-years; still as healthy as an average healthy adult human.

If your pet cat spends most of its time outdoors, it doesn’t mean that they will be gone sooner. Just make sure to make regular appointments with the vet. To make sure that they are really taken care of, you can also find ways to bring your outdoor cat back inside.

So, do you know now how old your cat is in human years? Or better yet, how old are you in cat years?

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