When you hold a newborn kitten in the palm of your hand, it is hard to imagine it growing up. But before you know it, your tiny kitten has transformed into a fierce, adult cat.

How long does this actually take? When do kittens become cats? Read on to find out how much time you have before your kitten turns into a cat, and what changes you can expect along the way.

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Kittens vs Cats: What’s the difference?

Just like human babies, kittens go through some rapid stages of development before they can actually be considered adult cats.

The most obvious difference between kittens vs cats is of course their size and proportions. A kitten’s head is disproportionately large compared to their body. As they grow, their body grows at a faster rate than their head, so it eventually catches up.

Kittens also go through a teething process. They develop baby teeth at around 3 weeks old. When they are 3 months old, these baby teeth start to fall out and are replaced with adult teeth. It generally takes 4 to 6 months for a kitten to be done teething.

As they grow up, you can also see a change in their fur. Kittens tend to have very soft, fluffy fur, whereas adult cats have a slicker, shinier coat. This does vary with breed, however. Long-haired cats tend to remain fluffy even as adults.

Another big difference between kittens and cats is their activity level. Growing kittens have a lot of energy and an uncontrollable need to play and explore. They don’t know their own limits yet, so you can expect them to get into some trouble every now and again.

Adult cats are much calmer. They stick to their routines and spend more time just sitting around, or sleeping. And the older they get, the more they sleep.

If you don’t know exactly how old your kitten is, use our guide on How To Tell A Kitten’s Age to find your answer.

When Do Kittens Stop Growing?

All well-fed kittens grow at a similar rate, no matter what breed they are. Kittens from larger cat breeds don’t grow faster, but they do take longer to become fully grown.

In general, kittens from normal-sized breeds take about 12 months to reach their mature size. This is followed by a period of 3 to 6 months where they fully fill out their adult form.

Larger breeds, such as Maine Coons, Ragdolls or Savannah cats, can take up to 2 years to reach full physical maturity.

The best way to track your kitten’s growth is to measure them at regular intervals (every 1 to 2 weeks). Measure their length from their nose to their backside, and measure their height from their paws to their backs.

If you see no difference in size over 2 consecutive weeks, it is safe to say your kitten has stopped growing.

When To Switch From Kitten To Cat Food?

As long as they’re growing, kittens need to be fed either their mother’s milk or a kitten milk replacer and, later, kitten food. In comparison to adult cat food, kitten food has a higher fat content and, consequently, is higher in calories. These extra calories help your kitten to grow into a full-grown adult cat.

For normal-sized cats this takes around 12 months. So for the first year of their life, you should feed them kitten food and kitten treats.

If you have a Maine Coon, or another larger cat breed, you should feed them kitten food for up to 2 years.

Once your kitten stops growing, you can start switching them over to adult cat food. Don’t make the switch overnight, or you will risk your kitty’s stomach getting upset.

Start by giving them a ratio of 3 parts kitten food and 1 part adult food. If they take to it, then you can slowly increase the amount of adult food until that’s all they’re eating. If they don’t like it, try a different food.

Keep a close eye on your kitten’s weight during this time. If you find they are packing on the pounds (or ounces, really), you are probably feeding them too much. Use our handy Cat Food Calculator to determine the exact amount of calories your cat needs.

When Do Kittens Calm Down?

During their first few weeks of life, kittens don’t do much more than eating and sleeping. But once they become active, you’ll have your hands full! Your kittens will start to play, climb the furniture and chase each other around the house until it drives you mad.

A kitten’s hyperactivity reaches its height between 12 and 18 months old. Which is no wonder, because you’re basically dealing with a teenager at this point.

After 18 months, junior cats start to mature behaviorally. They get more settled in their ways and their energy level starts to go down.

At 2 years old, your now adult cat is both mentally and physically fully grown. As they grow older, you can expect them to get less active over time, aside from the occasional zoomies. But be careful not to let them get too lazy!

Diabetes and obesity are real problems for cats nowadays, in large part because of the high amounts of carbs in commercial cat foods. Keep your adult cat active and fit by playing with them every day.

When Do Kittens Become Cats?

Generally speaking, it takes 2 years for kittens to become cats.

This may seem like a long time, but it goes by very quickly. Make sure to take lots of pictures every step of the way, because your precious kitty will change before your eyes.

And you will want to remember that cuteness when they knock over your favorite vase.

Once they are adults, their personality doesn’t change much, so you know what you are in for. Then you can simply enjoy the bond you have formed with them, hopefully for many years.