How Long Do Cats Grow to Reach Full Size? What Owners Should Know

If you’ve just gotten a kitten, you may be wondering, “how long do cats grow to reach their adult size?” No matter the kind of cat breed, from Sphynx to Siamese, your feline friend is sure to grow as big as they possibly can.

Your cat hits similar developmental milestones to a human baby in its lifespan. However, if you’re wondering, “when do cats reach full size?” you might not find a definitive answer. Unlike a human child, there is no specific age where you’ll know for sure that your cat has stopped growing and maturing.

There are, however, estimated age ranges where most cats generally stop growing and reach full maturity. So, if you have questions like “how fast cats grow?” and “when are cats fully grown?” you’re in the right place. This guide covers everything about cat growth to help you figure out when your little kitten will reach their full size.

Here’s what you can expect in terms of growth while you’re caring for your new kitten.

Cat Growth Rate: Milestones for Growing Kittens

The average kitten weighs around 3.5 ounces at birth. They usually double in size during their first week, after which they’ll grow about an ounce approximately every three days. They’ll continue to grow rapidly for the first few months.

Here are some important mileposts to look forward to for your kittens as they grow:

• Weeks 1-3: Kittens’ eyes and ears start opening up around the second week, and they become more aware of the world.
• Weeks 3-5: Kittens start taking their first (wobbly) steps. As they get more comfortable, they start running around and exploring.
• Weeks 6-8: Kittens become more playful, their baby teeth are growing out, and they receive their first few vaccines.
• Weeks 9-12: Kittens are weaned off and ready to try solid food.
• Months 3-4: The kitten’s rapid growth starts to slow down a bit. Baby teeth start to fall out and are replaced by adult teeth; this growth process usually ends by 6 months of age.
• Months 4-9: Kittens go through sexual maturation. This is when the cat has come into season or ‘call’. Cycles of sexual activity typically occur every two to three weeks. They also become very vocal during this time.
• Months 9-12: A kitten has almost achieved full growth.
• 1 year+: Kittens are entering adulthood, and most start reaching their full size.
• 2 years+: Around the age of two, cats are typically fully grown, and they are socially and behaviorally mature.

Larger breeds take generally longer to reach their full size; male cats grow for a longer period of time than female cats.

How Fast Do Cats Grow: Kitten Growth Chart

So how do cats grow in their first few months? Kittens typically grow eight times their size in just about eight weeks. Below is an estimation of your kitten’s potential growth based on the average weight of kittens. The weights mentioned are approximate and can vary depending on the breed and gender of the cat

• Under 1 week old: Kittens weigh less than 4 ounces.
• 7 to 10 days old: Kittens weigh 4 to 6 ounces.
• 10 to 14 days old: Kittens weigh 6 to 8 ounces.
• 14 to 21 days old: Kittens weigh 8 to 12 ounces.
• 4 to 5 weeks old: Kittens weigh 12 ounces to 1 pound.
• 6 to 7 weeks old: Kittens weigh 1 pound to 1 pound and 8 ounces.
• 8 weeks old: Kittens weigh 1 and a half to 2 pounds.
• 12 weeks old: Kittens weigh 3 pounds to 5 and a half pounds.
• 16 weeks old: Kittens weigh approximately 5 and a half pounds to 7 and a half pounds.
• 6 months to 1 year old: Approximately 8 pounds to 15 pounds.

How Do Feeding Habits Change With a Cat’s Growth?

Because kittens grow at such a rapid rate in their first few weeks, you’ll notice they eat quite a lot of food. In fact, some kittens may even need four meals a day to accommodate all that speedy growth.

For this reason, some experts recommend free-feeding kittens once they are weaned and eating kitten-friendly wet food or dry food. This way, they can eat as much as they need. If free-feeding isn’t something you’d like to try, feed your kitten three to four times a day at set times with about half a cup of food at each meal.

When they’re around six months old, and their growth starts to slow down a bit, you can adjust their feeding to around two to three times a day. After a year, as they approach their adult size, you can reduce the amount to two meals a day.

Tip: Always consult your veterinarian before making any sudden changes to their diet. Also, be sure to ask your vet how you can meet your cats’ daily nutritional needs.

When Should I Feed My Kitten Adult Cat Food?

The right time to transition your cat from kitten to adult food starts around 10-12 months of age.

However, if your little furball is struggling to keep weight on, it would be advisable to keep your furbaby on kitten food until they are two years old or even longer. This is because kitten food is usually more nutrient and calorie-dense to ensure healthy growth.

On the other hand, a kitten maturing quickly and becoming overweight on kitten food could benefit from switching to adult food as early as eight months. It’s always best to consult your vet when in doubt.

How Long Do Cats Grow For to Reach Full Size?

Now that you have a brief idea of a cat’s growth in their first few months, you may be asking, “when do cats grow to full size?”

Most experts agree that cats reach adulthood at 12 months old, which generally means that this is the age when a cat’s personality has matured and solidified into how they’ll behave throughout their adult lives.

However, a cat’s growth cannot be calculated with the same consistency. Some cats reach full size anywhere between 18 months to 4 years of age, so it’s hard to say at what age a cat is fully grown.

It’s important to note the best way to determine how long your cat will grow is by knowing its background. Your cat’s parents are the best indicator of most of your cat’s personality and physical traits. Your cat’s ancestry is the key to learning more about your cat, from its features to their gut health.

Gender can also be a factor in their size. Males tend to grow bigger than females, and the duration of their growth spurts can last longer.

Certain cat breeds may also reach their adult size slower or faster than others. Most small domestic cats may reach adult size around the age of one. While larger cat breeds like Maine Coon cats can take up to four years to reach their full extent. 

Factors That Affect Your Cat’s Potential Growth

Now that you know how large cats can get and how long cats grow for, you may have some questions about stunted or speedy growth in kittens. Below are some factors that can affect your kitten’s growth and are worth keeping in mind during their first few months.

Your Cat’s Food Consumption

One main factor that may stunt the growth of a cat is a poor diet. From birth, cats need to consume a massive amount of daily calories during their first stages of life to reach their proper size.

If cats aren’t fed properly, their growth can be stunted, which is why many previously homeless and abandoned shelter kittens are smaller in size and stature than their re-homed counterparts.

Tip: Have a look at these high-calorie cat food options if your cat is a bit underweight. As always, it’s best to consult a vet if you’re worried about your cat’s health.

Your Cat’s Breed

Another factor that contributes to your cats’ growth (or lack thereof) is their breed. The breed of your cat can affect its rate of growth. Unsurprisingly, the larger cat breeds take longer to reach their full potential of growth due to longer time periods to reach maturity.

When Your Cat Was Neutered or Spayed

However, in addition to diet and breed, the age at which a cat is spayed or neutered also affects your furry friends’ growth rate. Research has shown, a cat that is spayed or neutered early in its life can have slower or faster growth depending on the cat’s genetics.

Diseases or Conditions

Some diseases like Pituitary dwarfism and bone deformities can cause an afflicted cat’s growth to be slowed or stunted.

In contrast, some cats may have a rare condition called acromegaly, which causes an overproduction of growth hormones and enlarges the jaw, paws, and certain organs.

If you suspect your kitten may be afflicted by one of these conditions, be sure to have them checked by a medical professional.

When Do Kittens Stop Growing?

Once your kitten has made it past their first birthday, many cat parents wonder if that means their cat has stopped growing.

The short answer is, no. Although the most common age for a cat to stop growing is around 12 months, not all cats reach their full growth potential at this age. Although, if they are still growing as they age, it will be at a much slower rate.

This doesn’t necessarily mean cats over a year or two old will stop growing altogether. A cat who is mostly sedentary and has poor dietary habits can pack on fat. While a chubby, roly-poly cat is always cute, having an overweight cat is a very unhealthy condition for their general well-being.

Full-sized and Miniature-sized Outliers

Like most things in life, there is always an exception to any rule. These two examples below are an exception to the question, “when is a cat fully grown? (katieaustin.tv) ”.

You may notice that your cat seemingly keeps growing or hasn’t grown in months, similar to these two outlying cases below.

As mentioned earlier, the Maine Coon cat breed can take up to four to five years to reach full size. The Maine Coon cat, named Stewie, held the Guinness Book of World Records record for being the longest domestic cat, at 48.5 inches (123 cm) stretched out.

On the other side of the spectrum, cats with dwarfism can be abnormally small. Dwarf cats are the Lilliputians of the feline world. There are two different causes of dwarfism presented in cats: genetic mutation and a pituitary gland malfunction.

A miniature cat named Lilieput holds the Guinness Book of World Records record for the shortest cat. Lilieput measured at 5.25 inches (13.34 centimeters) from the bottom of the paws to the top of the shoulders.

How to Tell When Your Cat Has Reached Its Full Size

While it is true that cats can continue to grow after the first year, their growth rate will slow down significantly.

The best way to understand when your cat has stopped growing is to measure and weigh your cat once a month with a pet-friendly scale and measuring tape.

Cats continue to gain height (determined from the ground to the top of their shoulders) as well as length. If you measure your kitty once a month, you’ll be able to note when those measurements stop changing or change less. The stagnation in change indicates that they have stopped growing.

A cat’s weight can also reveal its maturity level or approximate age. You can estimate your cat’s adult weight by weighing them at 16 weeks of age and doubling that number.

Be sure to note that this is merely an estimation, and your cat’s weight may differ. In addition to using the scale to track your kitty’s growth, it can also help you keep track of any drastic weight changes. Sudden weight fluctuations may indicate that your cat’s health needs some looking into.

Final Thoughts on How Long Do Cats Grow?

While kittens will stop growing at about one-year-old, it’s important to remember that most kittens will look like an adult around six months.

Of course, the main takeaway is to feed your cat a healthy diet and regular veterinary check ups. Always provide your cat with a fresh water source and enrich their environment with plenty of stimulating activities, such as places to climb (eg, a scratching post) and spaces to explore.

These cat-caring practices will ensure your cat grows and matures efficiently. A strong and healthy cat is a happy cat, which is ultimately all we want for our furry bundles of joy.

Remember, no matter how big your cat gets, one thing is for sure, your cat will always need a record size portion of love, affection, and cuddles.