Shopping Cart


Your shopping bag is empty

Go to the shop

You’ve probably been told that one dog year is the same as seven human years, but is the formula really that straightforward? The formula for converting human years to dog years and cat years to human years is much more complicated. The first few years of your pet’s life equate to more human years than the following years because both animals mature faster than humans.

We know your feline companion is your precious baby, but you must remember that cats are still animals.

Your Cat’s Age in Human Years

Compared to us bipedal humans, they are still much closer to their wild roots.

The way humans have evolved to have long gestational periods followed by even more extended periods of intensive child-rearing and caregiving is a prime example of this. The gestation period for domesticated house cats is only 66 days. The kittens they produce only require a fraction of human babies’ care and attention. On the other hand, a self-cleaning litter box can be used to do the trim work they require.

Because of this, a one-year-old kitten is roughly the same age as a 15-year-old human in terms of development and physical maturity as a two-year-old cat. Then, equate each cat year to approximately four human years for each year after the first two. That would make a 5-year-old cat approximately 36 years old for a human.

Consider the following if you are having difficulty comprehending cats’ early maturation: Most of a kitten’s development occurs within the first six months. In fact, healthy kittens multiply by eight in just eight weeks! Cats reach their adult weight by the time they are about a year old, which typically ranges from 7 to 15 pounds, depending on the breed.

When your cat stops growing, how do you know? Between the ages of 9 months and 2 years, most veterinarians agree that your cat has finished growing. However, the full maturation of some breeds takes years. According to the American Animal Hospital Association (AAHA), learn more about a cat’s life stages.

Tracie Hotchner, the author of “The Cat Bible,” offers a slightly different approach to the previous calculation. Hotchner delves more specifically into the ages of young kittens and similarly young human children in this alternative formula. The response to the question, “How old do cats live in human years?” can be found here, courtesy of Hotchner.

  • A 1-month-old kitten is equivalent to a 6-month-old human baby
  • A 3-month-old kitten is equivalent to a 4-year-old child
  • A 6-month-old kitten is equivalent to 10 human years old
  • An 8-month-old kitten is equivalent to a 15-year-old human
  • A 1-year-old cat has reached adulthood, the equivalent of 18 human years
  • A 2-year-old cat is equivalent to a 24-year-old human
  • A 4-year-old cat is equivalent to a 35-year-old human
  • A 6-year-old cat is equivalent to a 42-year-old human
  • An 8-year-old cat is equivalent to a 50-year-old human
  • A 10-year-old cat is equivalent to a 60-year-old human
  • A 12-year-old cat is equivalent to a 70-year-old human
  • A 14-year-old cat is equivalent to an 80-year-old human
  • A 16-year-old cat is equivalent to an 84-year-old human

Suppose you used our cat years to human year calculator above. In that case, you might be curious as to why you were required to specify whether your cat lives exclusively indoors, outdoors, or combines the two. Sadly, a cat’s environment has a significant impact on its lifespan. If you ask a veterinarian, they will inform you: Cats that go outside are more likely to get hurt or hurt themselves.

Outdoor cats face exposure, predators, harsh conditions, and chronic “wear and tear” that can ultimately result in a shorter life expectancy, just as ancient men lived outdoors and had a life expectancy of 20–30 years. Compared to outdoor cats or even cats that live indoors and outdoors, indoor cats are the modern equivalent of opulent, secure royalty.

Regarding indoor and outdoor cats: Your veterinarian still needs to know about the small amount of time your cat spends outside, even if 90% to 95% of its life is spent indoors. Why? Because it has an impact on the diagnostics, vaccines, treatments, and care they provide for your cat.

Why, then, is a 5-year-old indoor cat in his prime (36 years old in human years) while a 5-year-old outdoor cat is already middle age (48 years old in human years)?”


There is a difference between a cat with a loving home who just happens to live outside and an outdoor cat without a home (also known as a stray or feral cat). The former’s lifespan is shortened when they are not spayed or neutered, get their vaccinations, and go to the vet regularly. However, even if your outdoor cat is spayed or neutered, vaccinated, and regularly visits the veterinarian, there are still numerous risks associated with living outside.

First, being outside can cause trauma. Your cat might be injured by the neighborhood bully, attacked by a dog or coyote, hit by a car, or beaten by the tomcat in the neighborhood. The most common problem with indoor and outdoor cats that veterinarians see in an emergency room is trauma. Trauma can cause broken bones, lung bruises, internal bleeding, and even death. Additionally, if you are fortunate enough to save your cat’s life, treatment could set you back several thousand dollars.

Next, being outside can be poisonous. Accidentally exposed to antifreeze in your neighbor’s driveway, your cat eating your neighbor’s tiger lilies or daylilies, or digging around for mouse poison can all result in death.

Last but not least, your cat might contract a disease or an infection that can kill it. Your cat could easily contract feline leukemia (FeLV) or kitty AIDS/FIV from fighting with other cats. Cornell Feline Health Center has more information about FIV and FeLV.)Additionally, your cat’s exposure to fleas, ticks, tapeworms, and other parasites increases dramatically when it goes outside. Your outdoor cat must be vaccinated and current on their FeLV and rabies vaccinations and on medication for heartworm, flea, and ticks throughout the year.

You might not be aware of your cat’s exact age if you adopted them. However, knowing your cat’s age can help you provide them with the best care. To help you determine your cat’s age, look for the following characteristics:

  • Fur: While older cats may have thicker, coarser coats, kittens and young cats typically have soft, smooth coats. An older cat’s fur might even have some grey in it.
  • Teeth: Cats usually don’t get every one of their teeth until something like a half-year-old, and more young felines generally have a lot more white teeth. You’ll probably notice more wear and tartar buildup as your cat ages.
  • Eyes: Older cats may have cloudier eyes, but this is not always the case, and younger cats may have brighter eyes.
  • Changes in hormones: An unsprayed female kitten may begin to mate as early as 5 months of age. The signs are territorial marking, mating calls, and a desire to flee outside.
  • Levels of mobility and activity: Compared to younger cats, older cats typically move less and are less playful. Older cats may also gain more weight if they get less exercise.

Despite the standard approach of converting cat years to human years to determine our cats’ ages in human years, this conversion can be used in either direction.

That is to say, the Cat Calculator estimates that a cat can live up to 20.8 years if you assume that a human can live up to 100 years. On the other hand, if you consider that, according to The Cat Bible, 16 human years are equivalent to 84 cat years, then a 100-year-old human could be compared to 525 cat years.

The way we experience time, the length of our human years, and the meaning we assign to particular numbered years (the big 3–0, for example) is a matter of perspective. Although this is generally a less practical way to consider the relative aging rate, it does serve as an important reminder. Other frequently cited ideas include: “You’re only as old as you feel” and “It’s not the years in your life, but the life in your years” are two examples.

According to the cat years to human years formula, how old is your cat? Or perhaps we ought to inquire about your age in cat years. 

Related post