How old is my cat? Is your kitty on a diet or finally getting healthy? Calculating the age of your feline friend can be quite challenging as they aren’t always very cooperative. We’re here to help you out in figuring out how many years your fuzzy family member has been with you!

The “cat age calculator” is a guide to calculating your cat’s age. It includes information about the different types of cats, their average lifespan, and how old they are when they start to show signs of aging.

There’s a popular belief that one canine year is about comparable to seven human years. Is the formula, however, truly so straightforward? The technique for converting dog and cat years to human years is really a lot more complicated. Humans develop at a slower pace than dogs and cats. As a result, the initial years of your pet’s existence are equivalent to more human years than the years after that. Use our cat age calculator to gain a better picture of how cat and human ages compare:

Age of the CatSelect the age of the cat

WhereIndoor-Only Outdoor-OnlyOutdoor-OnlyOutdoor-OnlyOutdoor-OnlyOutdoor-OnlyOut

In human years, how old is your cat?

Maturation in its early stages

We understand that your feline friend is your beautiful baby, but cats are also animals. We bipedal people are still lot closer to our wild beginnings than they are.

The way humans have evolved to have extended gestation periods is a prime illustration of this. We have even more rigorous phases of parenting and childcare. Domesticated house cats, on the other hand, have a 66-day gestation period. They give birth to kittens that only need a fraction of the attention and care that human newborns do. A self-cleaning litter box may take care of the tiny amount of effort they do need.

That’s why a one-year-old kitten is around the developmental age of a 15-year-old person, while a two-year-old cat’s physical maturity is nearly the same as a 25-year-old human. Following that, equate each cat year to around four human years for each year after the first two. A 5-year-old cat would be 36 years old in human years.

One year old and fully grown

Look at it this way if you’re having problems understanding early development in cats: The first six months of a kitten’s life are spent growing. Healthy kittens may grow up to 8 times their original size in only 8 weeks! Cats will weigh about their mature weight by the time they are a year old, which normally varies from 7 to 15 pounds depending on the breed. 

How can you tell if your cat is no longer growing? Between the ages of 9 months and 2 years, most doctors think that your cat’s growth is complete. Some breeds, on the other hand, need years to completely develop.

a different formula

The author of The Cat Bible, Tracie Hotchner, provides a somewhat different take on the calculation. Hotchner goes into further detail in this alternate formula, comparing the ages of newborn kittens to the ages of equally young human children. The answer to the question “How long do cats live in human years?” is provided by Hotchner.

  • 6-month-old human baby Equals 1-month-old kitten
  • A three-month-old kitten is equivalent to a four-year-old child.
  • A 6-month-old kitten is equivalent to ten human years.
  • A 15-year-old person equals an 8-month-old cat.
  • A one-year-old cat has attained maturity, which corresponds to 18 human years.
  • 24 cat years Equals 2 human years
  • 35 cat years Equals 4 human years
  • 6 years in human years Equals 42 years in cat years
  • 50 cat years Equals 8 human years
  • 60 cat years Equals 10 human years
  • 70 cat years Equals 12 human years
  • 80 cat years Equals 14 human years
  • 84 cat years = 16 human years

cat years to human years

The indoor vs. outdoor component in converting cat years to human years

You may be wondering why you have to indicate whether your cat is indoor-only, outdoor-only, or a mix if you used our cat years to human years converter above. The unfortunate reality is that a cat’s surroundings has a significant impact on their longevity. Any veterinarian will warn you that cats that go outdoors are more vulnerable to damage or injury.

Outdoor cats risk exposure, predators, hard weather, and chronic “wear and tear” that may contribute to a shortened life expectancy, much as ancient man lived outdoors and had a life span of 20-30 years. When opposed to outdoor cats or even indoor/outdoor cats, indoor cats are the contemporary equivalent of pampered, protected royalty.

Speaking of indoor/outdoor cats, even if your cat spends 90-95 percent of its time inside, your veterinarian still wants to know about the short amount of time he or she spends outside. Why? Because it has an impact on how they treat your cat and the tests, immunizations, drugs, and treatments they utilize.

So, why is it that a 5-year-old indoor cat is in his prime (36 years in human years) but a 5-year-old outdoor cat has already reached middle age (48 years in human years)?

Why do outdoor cats “age” more quickly?

There’s a distinction to be made between an outdoor cat that has no home (i.e. feral or stray) and a cat who has a loving home but lives outdoors. Lack of immunizations and regular vet appointments, as well as not being spayed or neutered, reduce the lifetime of the former. Even if your outdoor cat is vaccinated, visits the doctor on a regular basis, and is spayed or neutered, there are still a number of dangers to be aware of.


For starters, being outdoors might cause trauma. Your cat might be struck by a vehicle, attacked by a dog or coyote, harmed by a bully in the area, or beaten up by a tomcat in the neighborhood. Trauma is the most common problem encountered in veterinary emergency rooms with indoor/outdoor cats, according to veterinarians. Fractures, lung bruising, internal hemorrhage, and even death may occur as a consequence of trauma. And even if you’re fortunate enough to preserve kitty’s life, the expense of therapy might run into the hundreds of dollars. 


Then there’s the risk of poisoning while you’re outdoors. Death may come from anything as easy as your cat eating your neighbor’s tiger lilies or daylilies, digging around and discovering mouse poison, or being exposed to antifreeze in your neighbor’s driveway. 

Transmission of infection or sickness

Finally, the outdoors might expose your cat to infection or disease transmission, which can be lethal. Fighting with other cats may easily lead to your cat contracting feline leukemia (FeLV) or kitten AIDS/FIV, which is a blood illness. Also, taking your cat outdoors increases the danger of tapeworms, fleas, ticks, and other parasites. It’s critical that your outdoor cat be fully vaccinated against FeLV and rabies, as well as be on year-round flea, tick, and heartworm treatment. 

There are two perspectives on aging.

Though the most typical use of cat years and human years is to determine how old our cats are in human years, the conversion may be used in both directions.

That example, if you take the maximum age of a person to be 100 years, the maximum age of a cat, according to the Cat Calculator, is 20.8 years. On the other hand, if 16 human years are similar to 84 cat years, as The Cat Bible implies, then a 100-year-old human may be considered to be the equivalent of 525 cat years.

Though this is a less practical method of calculating the relative aging rate, it serves as a useful reminder… It is a question of perspective how we perceive time, the duration of our human years, and the value we attribute to certain-numbered years (such as the big 3-0). Other well-known quotes include: It’s not about the years in your life, but about the life in your years, and You’re only as old as you feel.

According to the cat years to human years calculation, how old is your cat? Or maybe we should ask, in cat years, how old are YOU?

Unsplash photo by Manja Vitolic

cat years


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“How old is a 13 year-old cat in human years” is a question that has been asked many times. The age of your cat can be calculated by taking the number of human years and multiplying it by 7. Reference: how old is a 13 year-old cat in human years.

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