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When Do Cats Stop Growing?

Updated: August 4, 2022 by Kristen Chapple

If you are a young cat’s parent, chances are you occasionally treat it like a baby. He willingly takes part in it and would never disillusion you – and why would he? It’s great to be hand-fed and pampered like a cute little kiddo he still appears to be. Even though your legs grow numb 15 minutes into his afternoon nap.

Maybe you aren’t realizing it: your baby kitten is becoming an adult. Even though the whiskers are still twice the length of the ears (and THAT is long).

Once you become aware of it as a simple fact of life, next thing to wonder is when do cats stop growing? For how long can you count on this little toddler’s clumsiness or long-legged teenager’s revelry?


Kitty Growth Depends on Many Factors

Is your kitto a moggy cat? (Trivia alert: moggy or moggie is a fancy word for mixed or unknown breed.)

If yes, it will be a bit harder to predict its growth rate. Generally, bigger cat breeds take longer to grow fully. But questions keep rolling: it’s hard to even foretell how big it’s going to be. With dogs, we can anticipate their future dimensions by looking at their paw size and leg length. No such luck with cats.

You might imagine yours would grow to the average size of a domestic cat, but then it turns out it carries remnants of a Maine Coon’s DNA. And so your fluffy little ball grows into a gorgeous, 20-pound monster.

Apart from breed, when cat stops growing will also depend on their early babyhood days. Did the kitten suckle or was it fed with formula from day one? How many brothers and sisters did it share the breasts with? Is it male or female, spayed or neutered?

As a rule, kittens who were separated from their mother too early are more likely to be stunted since their organisms had to slacken the growth to save energy. If yours was lucky enough to spend its first days with its mother, the next question is how many siblings did it have. If there were only two or three of them, there was enough food for everyone. Ingesting enough calories is paramount for a kitten’s early development.


But Your Kitto Will Become an Adult Before You Know It

While in their kitten-hood, cats grow very fast. From mere 3.5 ounces at the moment of their birth, they can reach up to 20 pounds, and even more! First weeks are crucial. If you want to determine how heavy your kitty will be when it grows fully, just weigh it at about 16 weeks. They should double that weight when fully grown.

Cat’s puberty starts at about six to nine months. Even though they are still kittens technically, they can make other kittens at this stage. This should be the right moment to consult your veterinarian about spaying or neutering, as many vets will prefer to do it before the animal’s full sexual maturation.

After the 6th month, the growth slows down and generally stops anywhere between 12 and 18 months. Even though it may appear that your kitty stopped growing somewhere around its first birthday, it probably isn’t true. Her personality is already fully formed.

That’s when their teenage period glides into adulthood. After 18 months of age, it may still appear they are growing, while in fact they are only gaining in weight and mass. As a rule of thumb, male cats will grow bigger and will take longer to grow. They will be juniors for up to 2 years.

But growth is a complicated matter, as cats’ and kids’ parents are very well aware. Physical growth is the most obvious aspect of a cat’s development, but it doesn’t necessarily follow the cat’s psychological development.

If your cat grows very slowly, maybe it’s time to take it to the vet. It might have an issue with pituitary gland that is responsible for growth. Or maybe problems with bones, or even dwarfism. While these issues are not common, it’s best to keep track of their progress by weighing and measuring their mass, height and length on a weekly basis. Growth is not just a matter of cuteness; it can tell you volumes about your cat’s needs and the way you’re treating it.

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