intelligent looking tuxedo cat

When Do Cats Stop Growing? A Guide to Your Cat’s First Year

Are you the proud servant of a brand new kitten and looking for all the information you need about its first year?

If you’re asking the question “when do cats stop growing?”, you’ve found the guide for you. This guide to your cats first year will teach you:

  • Nutritional requirements
  • When to get vaccinations
  • The stages of cat development
  • How to set boundaries
  • And strategies for healthy development

Basically, we’re going to teach you how to be the best cat servant you can be.

Your cat’s first 12 months are full of awww moments and viral Facebook photos. But make no mistake—they are vital to your pet’s development and survival.

There is a ton of bad information out there. That’s why we decided to make this complete guide to your cat’s first year. It’ll answer questions like when do cats stop growing and provide a ton of other helpful information along the way.

When Do Cats Reach Full Size?

Quick Overview A kitten is not simply a miniature cat.

The development from kitten to adult cat is a lengthy and fascinating process, complete with changing needs, behavioural shifts, and very important decisions for the caregiver.

Knowing what’s in front of you will help you prepare to meet those needs and ensure that your cat lives a long and healthy life.

Development can be broken down into 4 phases:

  • Birth – 7 Weeks
  • 7 – 12 Weeks
  • 3 – 6 Months
  • 6 Months – One Year

Most experts agree that the answer to “when do cats stop being kittens” is about one year.

Let’s break each phase down.

The First 2 Months

The initial 7-8 weeks are the most important in your kitten’s life.

These will almost certainly be spent with the mother. During this time, the foundation of their personality will be laid.

Nutrition is extremely important during this phase. The mother cat’s milk transfers antibodies to the kitten to help them fend off disease, but they are slowly weaned off it and introduced to solid food.

Even if you don’t personally have your kitten yet, observing their growth from week to week while still in the litter is a fascinating (and facial expression producing!) sight to behold. They’ll never again grow at this rate.

7 to 12 Weeks (Bringing Your Kitty Home)

Most pet servants (oops, we mean owners), bring their kittens home at this age.

We know it’s hard to resist these adorable, wobbly balls of fluff, but adopting a kitten too soon can create serious health risks and personality disorders. Most reputable breeders will let the kitten stay with the mother and littermates for 7 or 8 weeks.

Now that they aren’t with their litter mates, it’s up to your interaction with them to set the course.

Try activities like:

  • Hide and Seek
  • Play Fighting
  • Fort Building (so they can ruin it)
  • Running Around Everywhere

Get your kitten his first set of vaccinations by 8 weeks and the next set about 4 weeks later.

8-week old kittens can start eating wet cat food (something like ZiwiPeak would be ideal). But their tummies are small, so keep meals small and frequent.

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Tip: Make meals a routine! Teach good habits by feeding them at regular intervals and never leaving food out longer than 20 minutes.

3 to 6 Months

Ah, adolescence. This is when your kitty will start to mature physically, find its place in the social order, and start requiring different nutrition. Expect physical and behavioural changes.

intelligent looking tuxedo cat

  • Physical Development: The first thing you’ll notice is that his baby teeth will fall out. Don’t freak out if you find a tooth in the carpet. Since the gums might be painful, now is a good time to start a tooth brushing routine. Gently massage his gums with gauze and get some cat toothpaste. You might also notice your fluffy kitten is becoming a lean, mean mouse-catching machine. He will become longer, slender, and more physically mature. Some cats even begin sexual activity by this age (see the important note for this section).
  • Behavioural Changes: Warning: teenage hormone injection coming. Your kitten will start to find its place in the social hierarchy. It might even challenge the alpha cat. Don’t worry, this is just them testing the water of adulthood (and your patience!). They might be testy and moody, and males might start to get aggressive.

Note: Now is a good time to get them spayed or neutered. Most advocate waiting until 6 months to do it, but early spay or neutering is gaining steam. Young males will go searching for female friends, and females will start to howl in heat. If you’re not sure whether your cat is male or female you can read our handy article on how to tell the sex of a cat.


  • Trim their nails
  • Feed them kitten food
  • Use a cat brush to remove dead hair
  • Get scratching accessories
  • Be patient
  • Take photos!

6 to 12 Months

Most experts agree that a kitten is no longer a kitten at one-year old. By this time, they’ll exhibit most traits of an adult cat and have reached their full physical maturity. This is the time you need to let them spread their wings and fly. Play with them and set boundaries, but don’t be too clingy. By this time they need to be totally off kitten food and using the litter box whenever necessary. Just like a teenager, remember that they are in a very confusing time. Use a spray bottle to set boundaries (keep them off the stove!), and don’t let them shred your drapes.

Some breeds take up to 4 years (the same ages as Candy Cat!) to fully mature (Maine Coons), so don’t worry if things take a bit longer.


  • Never strike your cat
  • If they don’t respond to your voice, don’t panic.
  • They sometimes take in information without acknowledging you
  • Never feed them human food
  • Set boundaries with a spray bottle but don’t be too strict
  • Praise them when they do something good (but not as often as a young kitten)

Time flies, and before you know it your baby kitten will be a full grown adult. Cherish these moments. Your cat’s life will be forever intertwined with yours (and your Facebook friend’s).

A cat should stop growing after  about one year, but never be too impatient. Hang on and enjoy the ride!

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