At What Age Do Cats Stop Growing?

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Have you recently welcomed a kitten into your life and want to find out all you can about that pivotal first year of their life?

If you are looking for information about when they stop growing?

You will find all this out and more in the following guide, including:

  • Dietary recommendations
  • When you should get them vaccinated
  • Different stages in their development
  • Setting boundaries
  • How to ensure they develop healthily

Essentially, you are going to learn everything you need to know to be as good a cat owner as you possible can be.

During that first year of your new kitten’s life will involve a lot of ‘oh’ and ‘ah’ moments. There will be a lot of instagramming and Facebook shares. All of the fun and gushy stuff aside though, there is a lot of important things that happen that are crucial to your cat’s development.

If you have spent any amount of time browsing what’s out there in the way of information, you can be forgiven for feeling a little overwhelmed. There is so much out there, so much to read. This is why we have put together this post.

So, rather than spend a lot of time going round in circles, we have brought all the important stuff about your kitten’s journey to full size in one helpful place.

When Do Kittens Grow Into Full Size Adult Cats?

Before we go any further it is worth noting that you need to remember that a kitten is not just a small cat.

A kitten’s development into an adult cat can be a very interesting and long process, involving lots of changes in behaviour, needs and some important decisions to make for you, their owner.

Understanding exactly what lies before you can help you to ready yourself for the challenges and needs and give your cat the best chance possible of having a very long, healthy and happy life.

Your kitten’s development during that first year can be broken down as thus-

  • Birth to 7 weeks
  • 7 to 12 weeks
  • 3 to 6 months
  • 6 months to 1 year

It is widely agreed upon by most feline experts that kittens stop being kittens at around the 1 year mark.

Let’s take a closer look at each of the stages above.

From Birth to 7/8 Weeks

We are not being over the top or dramatic when we say that the most important period of time in your cat’s life is the first 7 to 8 weeks after they are born.

Under normal circumstances, during these weeks your kitten will spend most of the time with their mum. It is during this period that the seeds are sown as to the type of cat they will be ? what their personality will be like.

Their nutritional intake and diet are very crucial during this stage. Their mother’s milk contains antibodies that can help your kitten fight against diseases, but they are gradually and slowly weaned off it and are encouraged to start eating solid food.

Whether you have your kitten living with you yet or not, the progress they make while they are still communally with their litter is incredibly interesting. This is when they do the majority of their growing.

When Your Kitten Comes To Stay – 7 to 11 Weeks

At around 7 to 12 weeks, this is when most kittens move in with their owners….I mean slaves!

Although you may be compelled to take them on at an earlier point in their life, and let’s face it we can’t blame you really, they are incredibly cute balls of fur and big eyes; it can be detrimental to their health. Any reputable cat breeder who knows what they are doing and wants what’s best for the animals will keep the litter with their mother until week 7 or week 8.

However, once you have taken in your kitten and they are away from the other members of their litter, you are the one who needs to interact with them.

You could try some of the following:

  • Playing hide and seek
  • Running around everywhere and encouraging your kitten to chase you
  • Building forts, for them to knock down
  • Play fighting with them


Their first set of vaccinations should be arranged for by week 8 and then the 2nd set around a month later.


At around 8 weeks, kittens are able to start eating wet food. However, as their stomachs are still rather small, you should make sure they have smaller meals at frequent intervals.

Turn mealtimes into a routine. Help your kitten to form good habits by feeding them at the same regular intervals every day and only leave food out for them for 20 minutes maximum each time.

Adolescence – 3 to 6 Months

This is the point in your kitten’s development when they start to mature on a physical level. They also start trying to establish their position within the pack/family and need different nutrition. You should expect to see and experience chances in their behaviour too.

Developing Physically

The first big change at this stage that will happen is that their baby teeth will start falling out. So, don’t be alarmed if you start finding the odd tooth on the floors around your house. As their gums are probably going to be in a lot of pain, it is recommended that you start getting into a routine for brushing their teeth. All you need to do is start by gently massaging gauze into their gums and invest in some cat-specific toothpaste.

It is also likely that your cat has started to become a more lean and physically strong feline. In some cases, cats at this age can even become sexually mature.

Changes in Behaviour

As your kitten begins to find his footing and place in the social hierarchy of your household, if you have more than one cat, he or she might try to challenge the existing alpha cat. This is not something that you need to worry about as they are just trying to test the water a little. And are definitely trying your patience too.? They could even get a little aggressive or at least moody and become like a teenage ball of fur.

This is a great time to consider getting them neutered or spayed, because although many people will suggest waiting until for your cat to reach 6 months, the earlier you do it the better. Young female cats will start howling in heat and young males will do all they can to try and find some females.

Additional Tips

  • At this age you can begin trimming their nails
  • Start feeding them kitten food
  • Regularly spend time brushing their hair and grooming them
  • Start investing in scratching accessories such as scratching posts or even scratching towers and trees
  • Exercise some patience
  • Take as many pictures as you can and enjoy this time!

When Kittens Become Cats – 6 to 12 Months

As noted earlier in this post, most feline experts agree that kittens are no longer kittens and become cats by the time they are 1 year old. By the time they reach that age, they will already be displaying the personality traits normally associated with adult cats and will have peaked in terms of their physical growth.

It is at this time that you need to give them a measure of freedom and allow them to do their own thing. You can still play with them and set reasonable boundaries, but avoid becoming too clingy. They should also be weaned off kitten food completely by this time and be using their litter box. Treat cats at this age like you would teenagers, they are confused and a mix of hormones. Keep them away from the stove and stop them shredding furniture and curtains by using a spray bottle.

There are exceptions to every rule and some breeds, like Maine Coons for example, take at least 4 years to reach physical maturity. So, it is nothing to worry about if it takes a longer than 1 year for your cat to fully develop.

Additional Tips

  • Never hit your cat, even if they upset or annoy you.
  • If you think they are ignoring you, don’t panic or get into a blind rage
  • They may still be taking in the information but are just not acknowledging it
  • Avoid feeding them human food at all costs
  • Establish boundaries using a spray bottle, but try to avoid being too strict
  • Continue to praise them whenever they do something positive and good, but don’t go too overboard like you may have when they were just a kitten

Remember that time has a habit of flying by and before you really have time to appreciate it, your little fluff ball of a kitten has become a handsome fully grown cat. Take the time to enjoy the moments you have when they are still young and if you do everything right, you and your cat will have a long life together.