Cat Tips

When Do Cats Stop Growing?

It’s hard to deny the cuteness of a little kitten. It’s also hard to keep up with just how fast they seem to grow.

As much as we wish our cats could always fit in the palm of our hand, they inevitably grow and mature, eventually becoming independent adults.

Though every breed and individual is different, there are some consistent factors we can track across the life of every cat to make sure they are healthy and thriving.

For pet parents, raising a cat from a young age can be one of the most rewarding journeys that they ever take. It’s also a big responsibility, which is why today’s Spot Pet Insurance guide is all about helping you on that path.

We’re talking about feline life stages, growth expectations, factors that may influence their growth, and how to know if they may need a little push.

What are the life stages for most cats?

Like humans, cats have certain life stages that define periods of growth for them in terms of their size, strength, and mental maturity.

While every cat is different, we can use these life stages as a guide for tracking our growing cat’s health and supporting their needs.

Let’s start by breaking down each major life stage for our feline friends.

Newborn to six months

The first six months of your cat’s life are when they grow the most. Newborn cats are extremely small, weighing between 80 to 170 grams (around a quarter of a pound or less) when healthy.

They don’t stay this small for long. As the days roll by, you’ll likely see your kitten growing a little bit almost every day. Most cats should reach about six pounds by six months, although this can vary based on individual factors for your cat.

As their muscles, bones, and the rest of their body develops, kittens become stronger and heavier. Most pet parents weigh their kittens frequently during this stage — sometimes every day.

Partnering with a trusted vet to track and support your cat’s growth is recommended. They can help you determine a healthy weight for your cat as time passes.

To maintain healthy development, your kitten needs plenty of nutrients! It’s important to feed your cat the right food throughout their life, but especially during this initial stage. Most kittens should eat specialized kitten food until approximately 12 months.

Thankfully, because of their nutrient needs at this time, you don’t need to worry about overeating. Kittens less than six months old can, more or less, eat to their heart’s content. It is possible for a kitten to be overweight, but this may not be cause for a restricted diet. Always consult a veterinarian before changing your kitten’s diet.

Six to 12 months

Most cats finish the majority of their growth by the 12-month mark. Smaller breeds, such as Siamese cats, might reach this point a bit earlier (around eight or nine months), while larger breeds, such as Maine coons, take up to two or three times as long.

During this stage, growth continues at a fast rate, but not quite as fast as the first six months. Free feeding your kitten may no longer be the best approach; it’s typically time to start planned meal times and watch your cat’s diet more closely.

As your cat nears the one-year mark, they are entering the first steps of adulthood. Most healthy cats weigh between eight to 14 pounds at this point, depending on their breed, gender, and other factors.

One to three years

In the first year or two of adulthood, some cats may continue to grow at a much slower rate. While we mark 12 months as the climax of kitten growth, a cat is truly considered full-grown, closer to 18 months in most cases.

For comparison, a kitten at 12 months is approximately comparable to a human at 15 years, while a kitten at 18 months corresponds to a 21-year-old human.

Not only should cats physically reach adulthood at this time, but their personalities also become more set in stone. By two years, cats should have matured in their behavior, social capabilities, and certain parts of their instinctive independence.

Three+ years

After three years, almost all cats are completely done growing. If your cat is putting on weight, especially in sizable amounts, talk to a trusted veterinarian. Up to 63% of domestic cats in developed countries may be overweight or obese.

As your cat ages, they may become more mellow and independent. It’s important to maintain a proper diet and encourage plenty of physical activity so that your cat can stay healthy and happy!

By 10 or 11 years, most cats are becoming seniors. In a few years, your cat may start to lose weight as they grow older. Feline health is more fragile at this time than during the adult years, and a number of health conditions are more likely to appear.

What factors influence my cat’s growth?

All cats are different, which means all cats will grow a bit differently. There are plenty of different factors that can influence your cat’s rate of growth and size ceiling. Things like breed, gender, diet, and even neutering can play a role.


One of the most central factors in growth is a cat’s breed. Generally, cats in the same breed have similar growth patterns, while patterns between breeds can be wildly different.

On average, most breeds are fairly similar. Cats experience most of their growth in their first six months, then finish growing by 12-18 months. Smaller breeds finish growing sooner, while larger breeds finish growing later.


Male cats are typically larger than female cats. The difference may vary but can usually be expected to fall around one to two pounds.

Despite being bigger, mains can grow more slowly since they have more growing to do. You can expect a female cat to finish growing a bit sooner than a male in most cases.


Though it may surprise most pet parents, the timing of a neuter/spay (especially for male cats) can play a significant role in their early growth process.

A spayed male cat doesn’t produce certain hormones that would otherwise help them grow. This is especially crucial during the early months, so many veterinarians recommend saving the spay appointment until your cat is into the 6-12 month life stage.

This tip isn’t relevant for female cats, but it could help your male kitten stay healthy and safe as they grow. Delayed neutering for males can also help prevent dangerous urinary health conditions.

Individual factors

Your cat’s parents, genetics, how many siblings they have, and even birth order may influence their size and growth. Every cat is an individual, so all trends regarding size and growth should be taken with a grain of salt.

At the same time, if your cat’s size and growth vary significantly from healthy norms, you should talk to a trusted veterinarian to ensure it isn’t due to an underlying health condition.

Final remarks

Here at Spot Pet Insurance, we’re dedicated to helping pet parents at every step of their journey. From finding the right cat breed for you to learning about cat physiology, health, and personality, our Blog has all the resources you need.


  • Feeding Growing Kittens | VCA Animal Hospital

  • Kitten Growth & Development: First Year Milestones | BondVet

  • Owner and Cat-Related Risk Factors for Feline Overweight or Obesity | Frontiers Veterinary Science

  • When Do Kittens Stop Growing? How To Tell If Your Feline’s Fully Grown | Daily Paws

  • Perineal Urethrostomy Surgery in Cats | VCA Animal Hospital

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