The first several months of your kitten’s life are full of growth and significant milestones. It takes just six months for a 3.5-ounce (99 grams) newborn kitten to become a nearly full-grown cat, weighing about six pounds (2.7 kg) and looking more adult-like every day. However, this rapid growth can’t last forever — so when do cats stop growing?
Cats stop growing between 12-24 months old, but the growth slows dramatically by 9-12 months. However, large-breed cats (like Maine Coons and Rag-dolls) may not be full-grown until around four years old. Alternatively, some small adult cats stop growing in length and height at about six months old.
It’s hard to say that all cats will stop growing at 12 or 24 months because no two cats are the same — breed, genetics, diet, and getting your cat fixed all play a role in a cat’s growth process. To find out when cats generally stop growing, read on.
Table of Contents
The First Six Months of Kittenhood
Young kittens typically hit all of the significant milestones by the time they’re 60 days old. Along with learning to open their eyes, walk unsupported, and wean from their mothers, a kitten’s physical size sometimes doubles or even triples from one week to the next.
In the table below, you’ll see how quickly young kittens progress over a few short months.
| Age | Average Weight | Major Milestones | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Newborn | 3-7 oz. (85-198 g) | 2 weeks | 8-14 oz. (227-397 g) | Can see, smell, hear, and walk wobbly | 4 weeks | 12-21 oz. (340-595 g) | Can eat wet food and eliminate on their own into a litter box | 6 weeks | 1-2 lbs (0.45-0.9 kgs) | Can play, venture off on their own, and groom themselves | 8 weeks | 1.4-2.6 lbs (0.6-1.2 kgs) | Can feed without the help of mom and get fixed | 10 weeks | 1.8-3.1 lbs (0.8-1.4 kgs) | Can eat solid food and be adopted out to a family | 12 weeks | 2.2-4 lbs (1-1.8 kgs) | Can play for longer, sleep less, and build meaningful relationships with other cats and humans | 16 weeks | 4-5.5 lbs (1.8-2.5 kgs) | 20 weeks | 5-6 lbs (2.3-2.7 kgs) | 24 weeks | 6-8 lbs (2.7-3.6 kgs) |
How’s that for some growth? By the time a kitten reaches the six-month mark (about 24 weeks), she’s already grown 42-fold since birth — from weighing as few as 3 ounces (85 grams) when she was born to up to 8 pounds (3.6 kg) halfway through her first year.
Your kitten grows a lot during her first eight weeks! Watch the video below if you want to learn about each significant milestone a kitten hits as a youngin:
Getting Your Kitten Spayed or Neutered
Many pet owners believe that neutering or spaying a cat as soon as eight weeks can stunt growth long-term. However, the opposite is true — fixing a cat as soon as possible can delay the fusion of growth plates, meaning your cat may grow to be taller and could grow for longer.
To ensure a full-statured cat, consider fixing your cat before reaching sexual maturity as early as four months (the first heat cycle for female cats or territorial behavior in tomcats). Fixing your cat as soon as possible also saves you from having to care for (and adopt out) kittens after your cat unexpectedly gets pregnant.
Feeding Your Kitten a Proper Diet
During the first six months, what (and how much) you feed your kitten can impact when she stops growing later on in life. Providing a kitten food intended for adult cats can deprive her of the nutrients essential for healthy growth, like:
- Calories (kittens need lots of calories to keep up with their fast metabolism)
- Calcium
- Vitamin D
- Vitamin B6
- Protein
- Potassium
- Magnesium
- Folic acid
- Pantothenic acid
- Sodium
It’s essential to feed your kitten food specifically made for kittens 3-4 times a day at an appropriate calorie count for her weight. Otherwise, you may be unintentionally stunting your kitten’s growth, and she may reach an adult size far smaller than predicted.
A Cat’s Teenage Years: Six to Twelve Months
When a cat hits the six-month mark, she’s either in or near the point of puberty. Your cat may still be little and a bit rowdy (as most kittens are), but she’s nearing the point of being fully-grown. Specifically, most vets anticipate a cat’s adult size to be twice what she weighed at 16 weeks.
With that in mind, any extra height or length your cat adds until the 12-month mark will be minor and slow, with most of the visible changes being weight gain that helps “fill out” your kitty’s figure and make her appear less lanky. Instead of gaining one pound (453 grams) a month like she was during the first six months, your kitty may be gaining just ¼-½ pound (113-227 grams) a month.
If you see your cat daily, you may not notice that she’s gotten slightly taller or longer from one week to the next.
What Age Is a Cat Full Grown?
Typically, the one-year mark for a cat is when she crosses over into adulthood. A one-year-old cat can begin eating adult cat food, as the nutrition overload in kitten food may cause unintentional weight gain in adult cats with slower metabolisms. A cat usually continues to grow — albeit much more slowly — until she’s 18-24 months old.
Of course, a cat’s breed also plays a role. Not surprisingly, large-breed cats tend to grow for far longer than smaller cat breeds. Some breeds may continue to develop until they’re five years old — here are some suitable examples:
| Breed | Stops Growing At… | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Maine Coon | 3-5 years | Ragdoll | 4 years | Ragamuffin | 4 years | American Bobtail | 2-3 years | Norwegian Forest Cat | 2-3 years |
On the other hand, other cat breeds — like Siamese and Munchkin cats — may reach their full adult sizes between six and ten months.
Genetics Do Matter
All species of animals adopt physical traits from their parents. For example, a young cat may get her eye color, hair length, coat pattern, or even ear shape from her parents.
Additionally, a cat’s parents and adult siblings are a pretty good indicator of a cat’s future growth. Therefore, if your cat’s parents were short-statured and weighted 8-10 pounds (3.6-4.5 kg), and your cat is eight pounds after 12 months, she likely doesn’t have much growing left to do.
Growth Doesn’t Consider Weight
A cat’s growth plates may formally fuse around 15 months old, but that doesn’t mean your cat will be entirely done growing by that point — at least not in girth. When your cat is full-grown, she’ll be at her adult height and length, but is more susceptible to weight gain with a now-slower metabolism.
Feeding your cat too often or too many calories can cause obesity (weighing at least 10% more than usual), which can trigger the following health consequences:
- A 2.8-times greater risk of mortality
- Diabetes
- Lethargy
- Gastrointestinal issues
- Liver failure
- Cancer
- Dandruff
Technically, your cat can grow for ten years, though not in the way you may have hoped! To make sure your cat doesn’t pack on extra pounds, give her 15+ minutes of exercise a day and feed her 20 calories per pound of bodyweight.
Conclusion
The rate at which young kittens grow is wild, but the rapid growth only lasts about six months. Your cat will be full-grown and into her adult years between six months and a year (sometimes growing for as long as 18-24 months). Of course, this assumes you’re keeping your cat healthy via a nutritious kitten food diet, adequate exercise, and spaying or neutering your cat.
Additionally, your cat may be an outlier. In other words, your kitty may have parents who are both tiny (genetics) or end up at her full adult size by the time she’s 6-9 months old.
Sources
- Fetch by WebMD: Newborn Kitten Care
- Alley Cat Allies: Newborn Kitten Progression & Cat Age Chart with Pictures
- Animal Planet: Feline Puberty Arrives
- Colorado State: Early Sterilization in Dogs and Cats
- VCA Hospitals: Estrous Cycles in Dogs
- Pet Central: How Much To Feed a Kitten: Kitten Food Portions and Feeding Schedule
- VCA Hospitals: Obesity in Cats
- ResearchGate: Number of cats with open or closed physes at specified ages according to sex and neuter status
Pam is a self-confessed cat lover and has experience of working with cats and owning cats for as long as she can remember. This website is where she gets to share her knowledge and interact with other cat lovers.