When Do Cats Stop Growing?

One adult grey cat sitting next to small grey kitten. Both are looking at something in the distance


When Does a Kitten Become a Cat?

The day you bring home your cute little mischievous kitten is one of the most exciting days of a new kitten owner. Holding her in your hand might make you wonder how a creature so small could have such a big attitude. You might even wonder when she will grow into this big personality she already shows off.

Kittens grow rapidly into full-size cats; it often seems to be right before your eyes! It is good to know what to expect as your kitten grows up to ensure you are providing the best nutrients and environment for their health and safety.

When Do Cats Stop Growing?Small yellow kitten climbing out of a blue basket. The kitten's mother is in the background watching.

As your kitten grows up, you might wonder when they will stop growing.   At what point is a kitten considered an adult cat?

The answer varies based on several different factors, including what breed or sex of cat you have. In general, a cat is considered an adult by around 12 to 15 months of age. They will have some filling out to do at this point, but typically at a much slower pace than their first year of life. On average, a full-grown cat can be expected to weigh about 10 pounds but can range anywhere from 8 to 18 pounds.


Cat Growth Cycle

1 to 6 monthsTwo newborn kittens in the palms of 2 people's hands

  • Newborn kittens are born with both their eyes and ears closed. They start opening around 1 to 2 weeks of age. By 2 weeks old, their deciduous (baby) teeth start to erupt.
  • Kittens are raised with their mother until about 8 weeks of age, which is when they can be weaned.
  • Until about 6 months of age, a general rule for a healthy kitten is they will grow about 1 pound per month. A 1-month-old kitten will weigh about 1 pound; a 2-month-old kitten will weigh about 2 pounds, and so on until about 6 months of age.
  •  A kitten’s baby teeth will be replaced by adult teeth once it is around 3 or 4 months old and continue until 6 months of age.
  • Kittens up to about 6 months old are equivalent to human babies and toddlers.


6 to 12 monthsCute fluffy grey cat with bluish greenish eyes looking at the camera

  • Kittens reach sexual maturity during this juvenile period. It is often around this age that your veterinarian might recommend having your female cat spayed or your male cat neutered.
  • By this age, a kitten will have their adult teeth.
  • A kitten from 6 to 12 months is considered similar to a human preteen and teenager.


1 to 2 years

Yellow brownish cat with black stripes lying down looking at something in the distance

  • Once a cat is a year old, they are considered full-grown and comparable to a young adult human.
  • It is from year 1 to 2 that they mature into a fully developed and mature cat.


How Big Will My Cat Get?Huge white and brown/yellowish cat licking its nose

The average cat will weigh right around 10 pounds. The size and weight of your adult cat will vary based on several factors like breed, sex, and diet.


Breed differences

The International Cat Association (TICA) recognizes 71 different types of registered purebred cat breeds. This doesn’t even include all the varieties of mixed breeds commonly referred to as domestic short, medium, or long-haired cats.

While cats don’t genetically differ much from their ancestors, different breeds can have drastically different looks. From the hairless Sphynx to the large fluffy Maine Coon, there are many various colors, hair lengths, and sizes of cats.


Small Cat Breeds

  • Singapura cats are one of the smallest breeds that you can find. They typically don’t weigh more than about 5 pounds full-grown.
  • According to Purina, a few other small cat breeds include the Munchkin, American Curl, Cornish Rex, Devon Rex, and Siamese. As adults, these cats tend to weigh between 5 and 10 pounds.


Large Cat Breeds

  • Purina also lists some of the largest cat breeds.
  • Maine Coon cats have long been known to take the record, literally the Guinness World Record, for being the largest domestic cat breed. On average, a Maine Coon can weigh between 15-25 pounds!
  • Some other large cat breeds include the Persian, Savannah Cat, Norwegian Forest Cat, Birman, Ragdoll, Ragamuffin, and Chausie.


Male Versus Female

Like many species, males tend to be larger than their female counterparts. There is no specific range or exact difference, but they tend to have a larger muscle mass and stand taller and longer than females.


Spayed or Neutered Versus Intact

Cats that have been fixed (spayed or neutered) are not necessarily bigger but tend to gain more weight and are more prone to obesity than their intact feline friends.  This is because sex hormones help keep a cat’s metabolism in check. Once a cat is spayed or neutered, those hormones go away, and often the cat leads a more sedentary lifestyle and thus is prone to weight gain.


What Is a Healthy Size or Weight for My Cat?Vet putting a tan-ish black Siamese cat on a scale to check its weight

As mentioned above, several factors lead to a cat’s adult weight. It is important to take your cat for yearly veterinary checkups to make sure they are at a healthy weight for their age and breed.


Body Condition Score

Most veterinarians will use the body condition score to determine if your cat is underweight, at an ideal weight, or overweight. The World Small Animal Veterinary Association (WSAVA) has a standard chart that you can also use at home.

Ideally, you should be able to feel your cat’s ribs as you run your hands down their sides. You don’t want to see the ribs or hip bones sticking out. On the other hand, you don’t want to feel a lot of fat covering their ribs or have a big belly hanging down when they walk.


Health Conditions

Certain health conditions can cause or predispose cats to weight loss or weight gain. Cats losing weight might have gastrointestinal disease, hyperthyroidism, kidney disease, dental disease, or cancer. Cats that are obese are often predisposed to diabetes. It is essential to talk to your veterinarian if you are worried about your cat’s weight.


What Is the Best Food to Give a Growing Cat?

The best way to know how much food to feed your cat at any life stage is to talk to your veterinarian.  Feeding your cat according to the guidelines listed on their food bag is a good place to start. You can adjust this based on whether they need to gain or lose weight.

Most veterinarians will recommend that you feed your cat meals as opposed to free-feeding or leaving the food out all day. This will make it easier to measure the amount of food your cat is eating and to monitor how much they are eating. It is also easier to track weight loss and weight gain this way.

Typically, the best cat foods are from well-known brands rather than boutique brands.


Newborn kittens should nurse from their mother or be fed kitten milk replacer until their teeth come in, and they start eating wet or canned food, which is typically around 3-4 weeks From 4 weeks to about 6 weeks, kittens can transition to eating dry kitten food. A kitten should be fed dry kitten food or a mixture of wet and dry kitten food until a year of age.


Adult Cats

Once a cat is a year of age, they can eat regular adult cat food.


Senior Cats

When your adult cat grows into their senior years around 10 years of age, they should be transitioned to a senior-specific cat diet.

Cornell University has some great resources for feeding your cat and healthy weights.

As mentioned above, many interesting factors determine how big your little kitten will grow up to be. When you adopt a kitten, there usually isn’t much information about their history, so it can be hard to predict. The most important thing is to enjoy seeing your kitten’s personality blossom as they grow into adult cats.


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