When do cats stop growing?
Most cats reach their adult size between 12 and 18 months. Females often finish growing at around 10–12 months, males closer to 18 months. Large breeds such as Maine Coons, Ragdolls and Siberians can keep filling out for 2 to 4 years or more.
Kitten growth at a glance
| Age | Growth stage |
|---|---|
| 0–8 weeks | Fastest growth. Kittens roughly double their birth weight in the first week and are weaned by about 8 weeks. |
| About 6 months | Around 75% of adult size. |
| About 7–9 months | Growth slows as they near 80–90% of adult size. |
| 12–18 months | Most cats reach full adult size. |
| 2–5 years | Large breeds finish growing and filling out. |
Differences by sex and breed
- Females are usually done growing by about 10–12 months.
- Males can keep growing until around 18 months.
- Spayed and neutered cats may grow a little longer, because their growth plates close later.
- Large breeds: Maine Coons and Norwegian Forest Cats often grow until about 2 years or later. Ragdolls and RagaMuffins may not reach full size until around 4, and Siberians can take up to 5 years.
- Small breeds like the Singapura may finish by 9 months.
How to tell your cat has stopped growing
Weigh and measure your cat every few weeks. When their weight and length stay the same for several months on a steady diet, they’re likely full-grown. Your vet can confirm it, if needed, with an X-ray of the growth plates.
When to switch to adult cat food
Veterinary nutritionists recommend switching at 1 year of age or when your cat reaches maturity, whichever comes later. For most cats, start mixing in adult food at around 10 months and finish the switch by 12 months. Large breeds may stay on kitten food longer — ask your vet. Kitten food is rich, so staying on it too long can lead to weight gain.
Frequently asked questions
How big will my kitten get?
Breed, sex, parents’ size and nutrition all play a part. Most domestic cats end up around 8–10 pounds (3.5–4.5 kg); large breeds can be much heavier.
Is a 1-year-old cat still a kitten?
Cats are usually considered adults at 1 year, though many still act kittenish, and large breeds are still growing.
Do cats grow after being neutered?
Yes. Neutering doesn’t stop growth; it may actually let cats grow slightly longer.
Sources
This article is general information, not veterinary advice. Every pet is different — for questions about your own pet’s health, talk to your veterinarian.
