As much as we like it, kittens don’t stay like little hairballs forever. Inevitably, they grow into adult cats. Like other owners, you may be curious to know how fast and how long your cat will grow, what changes to expect as the months go by, and how to ensure that your pet is developing normally.

In this article, you will find a basic guide for cat owners on the growth phases and the different stages in the life of a cat, its nutritional requirements, the start of vaccination, the arrival of sexual maturity, and much more.

How long do cats grow? A guide for your kitten’s first year

The question of how long do cats grow or when do cats stop growing requires an answer with various nuances. For example, it is known that the growth time of a newborn kitten is highly dependent on its breed. Talking about how long a Siamese cat grows (it grows in a short time) is not the same as talking about a Bengal cat (it takes longer to grow).

Now, experts and breeders agree that most cats reach their full size between 8 and 16 months of age, with 12 months being the average growth period.

But the truth is that for any veterinarian this issue is not a matter of time, but of cycles and stages. To know when cats stop growing, it is not enough to pay attention to weight, height, or size; the progress of the pet must also be evaluated according to different phases.

A cat’s “stages in life” indicate when the feline is likely to reach important milestones. These include:

Be fully weaned

Have achieved the full range of vision and hearing
Exhibit the development of adult teeth
Eat independently

Be able to reproduce
Show changes in behavior (social and predatory skills)
Have completed the vaccination cycle for kittens

When do cats stop growing? How long do cats grow until fully grown?

Most breeders believe that the average cat grows to the first year of age. But it is noted that each breed grows at a different rate. It is known that some cats can take up to 5 years to become adults.

Stages in the cat’s life (growth, development, and care milestones)

According to experts, the growth of the common domestic cat is divided into 4 main stages. They are:

Birth to 7 weeks
7 to 12 weeks

3-6 months
From 6 months to 1 year

The first 2 months: opening your eyes to the world

The first 7-8 weeks are the most important in a kitten’s life. Usually, it has not yet been separated from the mother cat at this stage. The nutrition and antibodies provided by breast milk are essential for a kitty’s later development and good health.

By the second week of birth, the little cat should have opened its eyes and doubled its initial weight.

By the third week, the kitten is usually more active. It is advisable to encourage their sensory development, but without over-stimulating.

The experts assure that in this first stage the foundations of the personality are already established, hence it is important to establish playtime to promote social and intellectual skills.

In addition, it is said that if the mother is trained to use the litter box, she can start the training of her puppy herself, although it is best if the kitten has a box small enough to get into alone.

From 7 to 12 weeks: a discovery stage

This is the age that most kittens come home for the first time.

Your cat is growing, but the truth is that it still needs its mother. In the absence of the mother and her littermates, the pet relies heavily on interaction with its owner.

Although he can be active and energetic, the kitten does not have much life experience. It is normal for him to get into trouble frequently. It is advised that this is a good time to train him in the use of a harness/leash or a carrier.

Also, you may already need a larger litter box and scraper.

As for feeding after weaning, a food formulated for kittens should be introduced. At first, you may be hesitant, but you will soon accept it with enthusiasm. An 8-week-old cat may start to eat wet food, but consider her stomach to be small, so keep meals small and frequent.

What new skills can your cat learn in the second stage of life? Play hide-and-seek, fight, and race. It would also be a good idea to build structures for him to destroy.

The veterinarian usually indicates the first series of vaccines around the eighth week of life and schedules the next series for 4 weeks later.

3 to 6 months: adolescence

Adolescence has arrived! This is when your cat begins to physically mature, finds its place in the social order, and begins to require different nutrition. As an owner, you can expect noticeable changes in physique and behavior.

Physical development of the adolescent cat

The first thing you will notice is the loss of baby teeth. The gums may be sensitive, but it is a good time to start a tooth brushing routine. Gently massage the gums with gauze and apply some cat toothpaste.

You may also notice that the pussycat is turning into a muscular mouse-catching machine. The body will become longer, slimmer, and more mature. Even some cats can begin reproductive life at this age.

Behavior changes

The adolescent cats begin to find their place in the social hierarchy. They can become irritable, defiant, and moody, and males can become aggressive, especially if they are not spayed. It is also normal for them to try to get away with it.

Note: Although most people recommend waiting until 6 months of age in case you want to spay or neuter a cat, some believe that it is better not to wait that long.

At this point, the gradual transition from kitten food to adult food can begin. Likewise, it is recommended to provide them with larger toys, preferably something that they can chew while their new teeth come in.

From 6 to 12 months: the path to maturity

It is very likely that a 6-month-old kitten has already experienced the main milestones in its growth and development, but that does not mean that it has finished growing physically or psychologically.

Month 6

At 6 months of age, the kitten may look like a nearly mature cat, but that does not mean it has reached its adult size. The basic rule of thumb is that the average size cat gains about 1 pound per month, hence a cat this age can weigh about 6 pounds.

Their body may look a bit disproportionate, with a spindly torso and legs, but it will soon grow to adult proportions.

In this stage, the completion of the vaccination program and sterilization are major milestones.

Month 7

As a young cat, your pet usually sleeps more during the day, so expect to see him napping every so often. When he’s not asleep, he’ll spend time exploring and playing games. This shows that its confidence level is now higher.

You can also see that the cat behaves in a more social way, snuggling with you voluntarily. This is where all the socialization work pays off.

Month 8

The confidence level has reached its highest peak. Usually, an 8-month-old cat is old enough to play with other pets in the home, counterattack, push objects, and put them to the test.

It is said that in this phase it is important to set the limits well and be consistent in any type of training. Keep in mind that cats do not respond to force, so if you are trying to train them, you will need positive reinforcement and patience to get the result you want.

Verbal praise and cat treats can go a long way during feline training.

Months 9 and 10

By this time, the cat looks almost fully developed. Teething is over and its diet is that of an adult cat. It is common to observe biting and chewing behavior, hence you should take some measures in this regard. Consider that this can lead to aggressive behaviors.

Months 11 and 12

It has been almost a year of growth and the pet is about to become an adult. He is sexually mature, maintains a standard cat diet, uses the litter box, has received all his vaccinations, and continues to advance his social skills.

After one year of life, it is very likely that you have a real cat at home, with adult cat traits and full physical maturity. Remember that this can vary depending on the breed.

Cats at 1 year of age stop growing physically but continue to benefit from socialization and training. It is important to keep playing and interacting with them, and always set limits.

Denominations according to the age of the cat

Kitten: from birth to 6 months

Junior or adolescent: 7 to 12 or 24 months

Young adult: from 1 or 2 years to 6 years

Mature adult: 7 to 10 years

Senior: from 11 to 14 years old

Geriatric: 15 years and older

Newborn cats don’t stay small for long as they experience a steep growth curve. This is especially true during the first 9 months of life. How quickly a cat reaches adulthood depends on its breed.

Cat growth guidelines

So far we have seen a summary of how long it takes a cat to grow and what are the main changes at each stage of its life. But it never hurts to know what to expect in terms of physical measurements, such as length, weight, and height.

How long does my cat have to grow? Is it growing well?

As a newborn, a kitten only weighs a few ounces. In fact, it can easily fit in the palm of your hand. But from that moment on, it will start to gain around 7-14 grams per day. Between days 10 and 14 after birth, the kitten will have doubled in weight and size.

At this point, it is normal for him to gain 1 pound for each of the first 12 months of life. It is worth clarifying that weight gain in small or miniature cat breeds can decrease after 6-8 months of age.

Growth factors (by weight)

The following cat weight indicators can help you assess how well your kitten is growing.

Kitten 3 months (12 weeks). It should weigh between 2 and 4 pounds, with a size three to four times larger than at birth.
Kitten 4 months (16 weeks). It should already weigh between 4 and 5 pounds.

5-month-old kitten (20 weeks). It should weigh approximately 5 to 6 pounds.
6-month-old cat (24 weeks). It should weigh between 6 and 8 pounds.

For many cat breeds, reaching the 6-month milestone means they are between half and three-quarters of their full height and length. Keep in mind that a cat can continue to gain weight, length, and height beyond the first year. Again, that depends on the breed, the diet, and the particular cat.

Note: When it comes to assessing growth in cats, many professionals consider that weight, height, and length are not always reliable measures. It is known that these measurements can vary enormously, not only between different breeds, but also between individuals of the same breed, and even between kittens of the same litter.

Experts always recommend monitoring the growth of each cat individually, starting with weight, height, and initial length.

Factors such as breed and gender, among others, can influence whether a kitten is at the low end or the high end of the growth spectrum. But if you notice that your cat is growing too slowly, consult your vet without delay.

Cat/human growth comparison

Most cat breeds grow up to the first year of life. At this point, the cat’s body has reached adult maturity, its bones and muscles are strong, and its nutritional requirements have stabilized.

If we compare it with the growth process in humans, we have that a 12-month-old cat is equivalent to a 15-year-old person, and a 24-month-old cat is approximately equivalent to a 25-year-old person. From that moment on, each feline year is equivalent to 4 human years. For example, 5 feline years equal 37 human years.

That said, a 20-year-old kitten is like a 100-year-old human.

Growing cats and feeding

As you might expect, a growing kitten has higher nutritional requirements than an adult cat. Its diet should be rich in proteins, fats, essential vitamins, and minerals, especially in the early stages of life.

For example, proteins are necessary for the growth and development of strong tissues and muscles; fat is essential for energy and increases the absorption of certain vitamins; for their part, minerals play a decisive role in the development of bones and teeth.

As kittens have small stomachs, it is important to administer food in small and regular portions. Make sure you don’t over-feed.

Most veterinarians suggest feeding 3-4 times a day, not to exceed a 3/4 cup serving per meal. Once the cat reaches 6 months of age, it is a good time to cut down to just 2 meals a day.

Once the cat grows into an adult, its nutritional needs are not the same. As he approaches 10-12 months of age, he can begin to eat adult cat food.

But it really all depends on the particular cat. For example, a larger breed cat that takes longer to grow, such as the Maine Coon, may benefit from kitten food until he is 2 years old or older.

On the other hand, a kitten that is maturing quickly and already showing signs of being overweight may need a food change at 8 months of age.

Did you know? When a cat’s nutritional requirements are not met, it can grow very slowly, or even stop growing altogether.

A diet low in zinc, iron, potassium, sodium, and magnesium may stunt growth, and a diet high in calcium can also lead to denser, slower-developing bones.

Make sure you buy high-quality food for your cat.

At what age does a cat fully develop?

On average, house cats are considered fully grown when they are 1 year old. After the first 12 months, a young adult cat can continue to grow up to 18 months, but at a much slower rate.

Consider that there are some breeds of cats that take longer to grow, and may need between 2 and 3 years.

Do male cats outgrow female cats?

Male cats tend to grow to full size faster than female cats. That is why they are usually slightly larger and heavier than the females. Usually, the difference in weight is about 2 pounds, but this always depends on the breed.

What are the slowest growing cat breeds?

Typically, large cats take longer to grow and reach maturity. These include the breeds:

Maine coon
American bobtail
Bengal

British shorthair cat
Savannah
Ragdoll cat

How old do Persian cats grow?

The Persian cat usually grows to the age of 2 years, reaching an average weight of between 7 and 12 pounds.

How old do Siamese cats grow?

The Siamese cat grows to the age of 10-12 months and reaches an average weight of 10 pounds.

How long does the sphinx cat grow?

The sphinx cat takes 1 year to fully grow. In that time it reaches a weight of 6-12 pounds.

How old does the common European cat grow?

The European shorthair cat grows to 12-18 months of age. This medium-sized breed reaches 7 to 12 pounds as an adult.

How long does the Bengal cat grow?

The Bengal is one of the slow-growing cats, taking between 18 months and 2 years to reach its full size. Most of the specimens weigh about 16 pounds in adulthood.

When does the British shorthair cat stop growing?

The British shorthair cat grows to about 3 years of age. Their average adult weight is 15 pounds.

When does the Maine Coon cat stop growing?

Considered one of the largest pet cats in the world, the Maine Coon can grow up to the age of 4. Their average weight is 14 pounds.

How long do ragdoll cats grow?

Like the Maine Coon, the Ragdoll cat stops growing at around 4 years of age. During that time it can reach a weight of 10-15 pounds.

Important. The data presented above are approximate. The growth period of a cat can be influenced by several factors, regardless of its breed.

Is it possible to know how big a kitten will grow?

Many people claim that it is possible to guess how big a cat is going to be by looking at the size of its paws. Although the presence of high hind legs suggests that it is a large cat in training, the truth is that this is not considered a reliable indicator.

A kitten that has large paws and a more developed bone structure, or looks larger than the rest of the litter, can grow up to be a large cat, but this cannot be known for sure until the kitten has matured.

Do neutered kittens get bigger?

Yes. A cat neutered at a young age will grow longer and wider than a sibling neutered as an adult.

The arrival of puberty signals the cat’s body to stop growing, but if the cat is already neutered, the bones continue to develop longer.

Why doesn’t my cat grow like others of the same breed?

As with humans, cats of the same breed can be of different sizes. In fact, there are almost always cats smaller than others within the same litter. This may be due to factors such as genetics or access to the mother’s milk during the first weeks of life.

Just because a cat is naturally smaller than others of its breed does not mean that it is unhealthy.

What are the cats that hardly grow (stay small forever)?

Among the breeds of cats that grow less, are the Singapura cat, the American curl, the Cornish Rex, the Devon Rex, the munchkin, and the Siamese cat included.

How long do cats grow?

On average, cats grow to be 18 inches long, not including their tails.

How old do cats live?

Most cat breeds exhibit an average maximum age of 16 years. However, this can vary depending on the breed and lifestyle of the cat. The cats bred as pets at home have a life expectancy of 13 to 16 years, while the stray cats have a life expectancy of only 2-5 years.

Is a 1-year-old cat still considered a “kitten”?

The vast majority of cats are considered adults by the age of 1 year. The pet may still act mischievous and immature, but its needs are already those of a fully grown cat.

Do indoor cats grow bigger than outdoor cats?

In general, yes. House cats eat better than stray cats. Indoor cats grow larger than outdoor cats because of this and their low level of physical activity.

Final thought

The growth of a newborn kitten and its transformation into an adult cat is a fascinating process, in which the owner must make modifications and make important decisions.

Knowing how to recognize each of the phases and the changes that occur (physical, behavioral, etc.) will help you meet the needs of the developing pet cat. We hope that this guide has helped you better understand how long cats grow, what are the different factors that affect their growth, and what phases make up the feline life cycle.

Most cats grow until they are 12 months old, and can last as long as 18 months. Ultimately, how long your cat grows will largely depend on its breed.

Resources: