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When does a kitten become a cat?

Many pet parents have asked us, "When does my kitten become an adult cat?". Our Astoria vets answer this and other frequently asked questions about kitten growth and development, along with your growing cat's changing needs, in this article.

How long is a cat considered a kitten?

Your kitten will be an adult cat around the time they turn one year old. Keep in mind that some breeds, such as the Maine Coon, continue growing until 15 months. While your little ball of fur may still be full of energy and mischief, his nutritional and dietary requirements will have changed. 

The Stages of Kitten Growth & Development

Your kitten will go through many changes on their way to becoming an adult cat. Here's what happens from their first week into adulthood:

From 1-2 Weeks

By the end of their second week, most kittens will open their eyes for the first time. They suckle on their mother and will likely gain anywhere from 10 grams to 30 grams of weight per day. Their weight must be monitored carefully during these early stages, as weight loss may be dangerous to a little kitten. You and your vet can use a kitten weight chart to track their weight as they grow. 

After 4 Weeks 

Your kitten's personality will start to shine through and they'll be playful and eager to explore the world by the time they turn one month old. You can start feeding them solids gradually at this point. 

They should be much more independent from their mother as a food source by the time they are two months old. Their milk teeth should also start coming in. 

After 8-12 Weeks 

Your feline friend will be ready for their first vaccines by the time they are between 8 and 12 weeks old. They can be separated from their mother at this point and will also be ready for adoption. 

By 4 Months 

You may notice your kitty's baby teeth falling out and being replaced by adult teeth. Your kitty should have a complete set of new teeth by the time they are seven months old. 

By 6 Months 

Your little furball has grown close to its adult size by the time they reach six months of age. While they will continue to develop until they are one, they won't grow much bigger than they are now. 

Your kitten should also be spayed and neutered at this age if they haven't had this procedure done yet, since females will be starting their heat cycles and male kitties will start to display mating behavior like pacing, roaming, fighting and spraying. 

After One Year 

Your kitten will have become a cat once 12 months have passed. Though some breeds will have some more growing to do, they've usually reached their final size and should be fully socialized by this point. 

How a Kitten's Needs Change as They Grow

Though your kitten will be fully grown by the time they turn one year old, they will still have some developmental milestones to hit. However, these turning points will be less noticeable than the previous ones.

Now that he's fully grown, he'll have health and nutritional needs you'll need to tend to. Specifically, these include:

Diet & Nutrition 

Your kitten's food can significantly influence their growth rate. Since adult cats don't use as much energy as kittens, continuing to feed him kitten food may cause him to become overweight.

Feeding your cat a high-quality, protein-rich wet food with suitable levels of vitamins, nutrients and minerals will help him reach his adult size faster than if you were to provide food high in carbohydrates. 

Kittens slowly begin to eat solids once they are separated from their mothers, so introduce meat into their diet immediately. Grains, sugars and other carbohydrates are usually found in dry cat food. However, cat kibble is suboptimal compared to wet food and can result in dehydration and weight gain, which can leave your kitty prone to developing cystitis or struvite crystals. Kitty biscuits can be given as occasional treats. 

Forming good habits from kitten-hood and continuing them into adulthood is crucial to your kitty's health. Your vet can recommend a suitable adult cat food and provide advice on transitioning to the new food, along with any other questions you may have. 

It's a good idea to transition him slowly from the kitten food to his new adult food, introducing it gradually over 5 to 10 days to help him get used to the new taste and consistency. 

Routine Exams

Wellness exams are essential to helping your cat maintain good long-term physical health. When you bring your pet in for their annual checkup, your vet will perform a physical examination and look for signs of illness or disease, since early prevention and detection are key to diagnosis and effective treatment. 


When your cat is about 14 months old, your vet will likely recommend a booster vaccination to help maintain his immunity to many illnesses and diseases. This is also a good time to make sure your cat is protected against parasites by updating her flea and deworming treatments. 


Now that your cat is bigger and has more muscle, regular exercise is essential to help him stay fit and healthy. Exercise will keep his mind and body healthy, happy and active. 

What other factors can affect my kitten's growth and development?

A variety of factors can impact how much your kitten grows and at what rate. You can easily find growth charts for your kitten's breed online to understand more, or ask your vet about your kitten's individual growth and development. Some factors that can affect your kitten's growth into an adult cat include:


Different types of cats grow at different rates, and to different sizes. Large breeds tend to grow and develop more slowly than smaller breeds. If you're unsure of whether your kitten is the proper size for their age, consult your veterinarian. 

Spaying or Neutering

The age at which you have your furball spayed or neutered also affects their growth rate. Your cat's appetite may increased drastically once they've had this surgery to sterilize them, so you'll need to prevent them from overeating and becoming overweight. Obesity brings numerous health risks, such as diabetes and urinary tract issues. 

To keep your cat's growth on track following their procedure, ask your veterinarian about any recommended dietary changes, feeding schedule, and portion size. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Do you have questions or concerns about your kitten's growth and development? Contact our vets at Steinway Court Veterinarian to schedule an appointment.

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At Steinway Court Veterinarian, we are always accepting new patients. Our vets are dedicated to keeping pets healthy and happy in our Astoria clinic. Contact us today to book your first appointment.

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