How Big Will My Cat Get And When Is It Fully Grown? (Including A Kitten Weight Growth Chart!)

“How big will my cat get?”

If you’re a new cat owner and you just got a cute young kitten, then you’ve probably asked yourself this question.

How big your feline friend gets will depend on several factors, some of which have to do with your kitty’s upbringing, though most of which has to do with breed.

Regardless of your cat’s breed, though, it will grow fastest during the very first months. By the time it reaches 6-8 months, your kitten’s growth will have slowed considerably. Most cats reach their full adult weight and size by the end of the first year.

However, big breeds like the Maine Coon and the Ragdoll will keep growing even after their first 12 months, and will keep getting bigger up to the eighteenth month.

Healthy Cat and Kitten Weight & Growth Chartcat and kitten growth chart

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While every cat is different, there are some very general guidelines that might help you as you search for your cat’s final size.

We took a look at a few charts that gave rough size estimates, and put them all together on one graph (above).

As you can see, there’s a wide range of ideas as to how big and fast your pet will grow, though they all follow roughly the same pattern.

Note that the average size adult cat should weight about twice as much as it did at the 4 or 5 month mark. What you could do is weigh your cat at 16 weeks (use a food scale or something else small to get a more accurate weight measurement), and times it by 2. Anything within about 10% of this number, up or down, is a pretty good estimate for final size.

Estimated Cat Weight Equation


Kitten Weight At 16 Weeks * 2 = Adult Cat Weight


While male cats tend to be bigger than female cats, the difference is not huge, so you can still follow this loose formula.

Height is a bit more tricky, because there’s not a lot of data available. I’ve seen reports from parents of small cats around 6 or 7 inches tall from ground to shoulder, but then I’ve seen larger cat breed parents come up with 12-15″ tall at the shoulder.

Of course, there’s all ranges in between and it’s also tough to get a proper reading since you’ll be relying on your cat standing perfectly straight and perfectly still while you measure, and honestly when does that ever happen?

When Is My Cat An Adult, When Is It Fully Grown, and When Do Cats Stop Growing?

Cats can be considered adults around the time their growing slows down, between 9 and 12 months.

Sexual maturity in kittens is reached fairly quickly, coming anywhere between 6 and 9 months.

Keep an eye on weight and length to determine when your cat stops growing, and be cautious of him or her around members of the opposite sex if you have not had your cat spayed or neutered – they become sexually active much quicker than you might expect!

Are Indoor Cats Bigger Than Outdoor Cats?

Supposing one cat from a litter is left to be an outdoor cat, and one cat from the same litter is raised indoors, there’s not going to be an immense difference in their growth.

However, you might expect the outdoor cat to be on the lighter side, simply because the indoor cat is presumably being fed everyday (and potentially overfed) by it’s proud human.

The outdoor cat will need to fend for itself. Of course cats are evolved to live outdoors and eat wild animals like mice and rabbits, so it’s not bad for a cat to have to fend for itself! It might just go hungry from time to time, as is the way of things in nature.

Large Cat Breeds And What To Expect

maine coon size
How big can Maine Coons get? HUGE!

Maine Coon

These cuddly giants are the largest domestic cat breed, and can weight anywhere between 10 and 25 pounds (maybe even larger!), depending on the height and whether it’s a male or female.

They can grow 3 to 4 feet long, from the tip of the nose to the tip of the tail.


The result of breeding a male serval (wild African cat) with a female Siamese, Savannahs can get rather large, particularly if they’re closer genetically to the male serval descendant.

They can range anywhere between 8 and 20 pounds, depending on sex and genetics (which can vary greatly even amongst one litter).

Caring For Your Cat, No Matter The Size

Taking proper care of your cat will ensure that it reaches its full potential in terms of size, social maturity, and health. Here are some basic health and wellness tips to make sure your kitty grows up healthy!

  1. Neutering or spaying your cat at a young age or underfeeding it will suppress your kitty’s growth.
  2. On the other hand, if you’re spoiling it too much, overfeeding it, or filling its food with tons of vitamins, this may cause your cat to eventually develop obesity.
  3. Indoor cats and outdoor cats have different dietary needs due to their activity levels and the fact that the outdoor cat may be hunting for his food as well.
  4. Newborn kittens also need a special diet and lots of kitty vitamins, otherwise they won’t get the nutrition they need in order for them to grow big, healthy, and thriving.
  5. Some cat breeds need automatic feeders and special portions on a more frequent basis, like the Sphynx, otherwise they may grow obese or remain smaller and underfed.
  6. You should always consult with a vet when getting a newborn kitten not only for vaccines and possible diseases, but also for food, vitamins, and other supplements.

Keep in mind that your feline friend’s first year (and especially its first 6 months) is of extreme importance for its social and reproductive maturity, for its size and weight, and for its overall social behavior. Make sure you’re taking proper care of your precious furball and it will reward you with a lifetime of loving memories.

Emily Parker

Emily Parker is the Content Manager at Catological. She's passionate about helping cat parents love their cats better by providing the best information and recommendations about everything you'll need to know about your cat, from kitten to senior years. She believes natural, biologically-appropriate products are best...why wouldn't you provide the best for a member of your family?!

3 thoughts on “How Big Will My Cat Get And When Is It Fully Grown? (Including A Kitten Weight Growth Chart!)”

  1. Hi Emily, Nice site and great post! Just a reminder not to trust spellcheck features, though. You refer to “spraying” throughout the post, and of course you mean “spaying.”

  2. My male cat is eight months old he weighs 15 pounds I’m not on sure of his breed he is a rescue orange tabby he definitely looks fat. we have been using Temptations to train and he’s has a voracious appetite for that plus he eats his housemates share as well. looking at him from the side his sides are sticking out at present. We are using a grain free food now, adult but I don’t know if he’s just a big boy or we’re overfeeding. The other cat is on the thin side. She stopped eating after we lost several cats. I’m worried Moses is keeping her from eating. We’ve always free fed kibble for 30 yrs, maybe we need to somehow feed him separately while not eating his housemates food who does free feed. Any ideas would be welcome. I’ve had a diabetic cat before, I want to stop his from becoming overweight. Plus my last 3 cats were sick and thin. Maybe he’s got coon cat in him.

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