# When Do Cats Stop Growing? Full Size by Age Most cats reach full size somewhere between 10 and 12 months of age, though the exact finish line depends on breed, sex, and whether your cat was neutered. Large breeds like the Maine Coon can keep filling out until they are 2 years old or a bit more. If you want to know when do cats reach full size, the honest answer is that it varies, and the sections below show you how to track it at home. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Most domestic shorthair and longhair cats stop growing in length and height by about 12 months, then add a little muscle and body condition over the next few months. - Large and giant breeds mature later, often closer to 18 to 24 months. - Male cats are usually bigger than females and tend to finish later. - Cats neutered before puberty can grow slightly longer and end up slightly longer in the leg bones, because the growth plates close later [1][2]. - A cat that is still visibly growing after 2 years, or that is much smaller than its littermates, should be checked by a veterinarian. ## How Cats Grow: What Happens Month by Month Kittens do most of their skeletal growing in the first several months of life. Growth plate activity is the engine behind this. Growth plates are areas of soft, dividing cartilage near the ends of the long bones. When a growth plate finishes its work, it closes and hardens into solid bone. Once that happens, that bone cannot get longer. In cats, the timing of growth plate closure is not identical across the body. Some plates close early, others later. Research on the forelimb found that the distal radial physis, the growth plate near the wrist, closes at different times depending on sex and neuter status [1]. Work on the hind limb looked at the greater trochanter, proximal femur, distal femur, and proximal tibia and found that these physes also close at different ages, with neutered cats closing later than intact cats [2]. One useful detail for owners: cats do not have a clear pubertal growth spurt the way humans do. A study that tracked radial growth in kittens found no puberal growth spurt in any of the cats observed [1]. Growth is steadier than you might expect. That means a sudden, dramatic change in size is not normal and deserves attention. ### When Do Cats Become Full Grown? For most cats, the answer is around 1 year. Body length and leg length are largely set by then. After that, many cats continue to gain a small amount of weight and muscle, which owners often notice as the cat "filling out." This is normal and is not the same as bones getting longer. ### When Do Cats Reach Adult Size by Breed Breed matters a great deal. Small and medium cats, including most mixed breeds, finish early. Large breeds finish later. The table below gives general ranges that veterinarians use as a guide. These are typical ranges, not guarantees, and individual cats vary. | Cat type | Typical age at full size | Notes | |---|---|---| | Domestic shorthair or longhair | 10 to 12 months | Most reach adult length by 1 year | | Small breeds (for example, Singapura, Cornish Rex) | 9 to 12 months | Often finish on the early side | | Medium breeds (for example, American Shorthair, Russian Blue) | 12 to 15 months | Slight filling out after 1 year | | Large breeds (for example, Maine Coon, Norwegian Forest Cat, Ragdoll) | 18 to 24 months | Bones and body condition mature later | | Giant breeds (for example, Savannah, Maine Coon males) | Up to 2 to 3 years | Slowest to finish, especially males | If you are not sure what breed mix you have, assume the domestic shorthair timeline and watch your cat's body condition instead of the calendar. ### Does Sex Change the Timeline? Yes, a little. Male cats are generally larger and finish growing later than females. In the forelimb study, male and female cats differed in which growth plates closed when, and the final radial length was longer in neutered animals of both sexes [1]. In practice, this means a male cat may still look like he is "growing into his paws" at 12 months while his sister looks done. ### Does Neutering Change Growth? This is one of the most common questions owners ask, and the research is clear. Neutering before or after puberty delays growth plate closure in cats [1][2]. In one study, distal radial physeal closure was delayed in both groups of gonadectomized males compared with intact males, and in females, both proximal and distal radial physeal closure were delayed in gonadectomized animals compared with intact animals [1]. Final radial length was significantly greater in all gonadectomized animals [1]. A separate study of 808 cats found a statistically significant effect of neutering on physeal closure times, with physes closing later in neutered cats [2]. Another study on prepubertal ovariohysterectomy in female kittens examined bone density and proximal radial physeal closure and found no significant differences in bone mineral density or bone mineral content between groups during the study period [3]. What does this mean for you? A neutered cat may end up slightly taller or longer in the leg than an intact cat of the same breed and sex. This is a normal, expected effect and not a health problem. If you are planning neutering, talk with your veterinarian about timing. You can read more about typical timing in our guide to [Cat Neuter Age](/knowledge/veterinary-medicine/preventive-care/cat-neuter-age). ## How to Track Your Cat's Growth at Home You do not need X-rays to know whether your cat is on track. You need a scale, a tape measure, and a routine. 1. Weigh your kitten on the same scale at the same time of day, ideally before breakfast. Use a kitchen scale for small kittens or a baby scale for larger ones. 2. Record the weight in a notebook or phone app every 2 weeks until 6 months, then monthly until 1 year. 3. Measure body length from the base of the neck to the base of the tail with a soft tape measure. Do this monthly. 4. Take a photo from the side and in published veterinary research each month. Photos show body condition changes that the scale can miss. 5. Compare your cat's weight curve to the growth chart your veterinarian uses. Ask for a copy at your next visit. 6. At each veterinary visit, ask whether your cat's weight and body condition score are appropriate for its age and breed. A steady upward curve that flattens around 10 to 12 months is normal for most cats. A curve that flattens too early, or that drops, is a reason to call your veterinarian. ### Growth Checklist by Age | Age | What to expect | What to do | |---|---|---| | Birth to 8 weeks | Rapid weight gain, eyes and ears open, nursing or bottle feeding | Vet visit, deworming, first vaccines per your vet | | 2 to 4 months | Fast growth, kitten teeth coming in | Monthly weigh-ins, vaccine boosters, discuss neuter timing | | 4 to 6 months | Growth still fast, sexual maturity approaching | Continue weigh-ins, schedule neuter if planned | | 6 to 12 months | Growth slows, body fills out | Monthly weigh-ins, watch body condition | | 12 to 24 months | Most cats done, large breeds still growing | Annual exam, ask about weight trend | | Over 24 months | Growth should be complete | If still growing, ask your vet | ## When Do Cats Stop Growing? Signs Growth Is Complete You can look for a few practical signs that your cat has finished growing. - Weight has been stable within a small range for 2 to 3 months. - Body length has not changed on your monthly measurements. - Your cat's body looks proportional, with the head, body, and legs in balance. - Your cat has reached the typical age range for its breed and sex. If your cat is 14 months old, weighs the same as it did at 11 months, and looks proportionate, it is almost certainly done growing. If your cat is a Maine Coon at 14 months, it may still have months to go. ## Signs Something Is Wrong Slow growth is not always a problem. Some cats are simply small. But certain patterns need a veterinary visit. - Weight loss or a flat weight curve before 10 months. - A kitten that is much smaller than its littermates at the same age. - Visible lameness, reluctance to jump, or swelling near a joint. - A potbellied appearance, dull coat, or poor appetite. - Diarrhea or vomiting that lasts more than a day or two. - A cat that stops eating or drinking. - A cat that has not urinated in 24 hours, which is an emergency. Growth problems in kittens can come from parasites, intestinal disease, heart disease, hormone problems, or nutrition. Your veterinarian can sort out which one is at play. If your cat is not eating or drinking normally, our guide to [How Long Can A Cat Go Without Peeing Or Pooping](/knowledge/veterinary-medicine/symptom-guides/how-long-can-a-cat-go-without-peeing-or-pooping) explains when to worry. ## Common Mistakes Owners Make - Feeding a kitten adult food too early. Kittens need more calories, protein, and minerals per pound than adults. Ask your veterinarian when to switch. - Free-feeding without measuring. This hides how much your cat actually eats and makes weight tracking useless. - Assuming a small cat is stunted. Many cats are simply small, and that is fine if they are healthy. - Comparing your cat to a littermate. Littermates can vary in size for many reasons, including sex and genetics. - Skipping the 6-month and 12-month exams. These visits catch growth and body condition problems early. - Ignoring a sudden change in appetite or water intake. These can signal illness at any age. ## Supplies and Setup That Support Healthy Growth You do not need much, but a few items make a real difference. - A digital scale that reads in small increments. A kitchen scale works well for kittens under 5 pounds. - A soft tape measure for body length. - A notebook or phone app for weight and length records. - A kitten-formulated diet until your veterinarian says to switch. - A shallow litter box that is easy for a young kitten to step into. - A quiet, warm sleeping area away from loud household traffic. - A scratching post and safe toys to support normal development. If you are adding a second cat to the home while your kitten is still growing, our guide to [How Long To Introduce New Cat To Old Cat](/knowledge/veterinary-medicine/clinical-methods/how-long-to-introduce-new-cat-to-old-cat) walks through a slow introduction. ## Limitations and When to Contact a Veterinarian Growth timelines are averages, not rules. Your cat's breed, sex, neuter status, genetics, and nutrition all shift the timeline. No article can tell you whether your individual cat is on track. That requires an exam, a weight history, and sometimes X-rays. Your veterinarian is the only one who can do that for your cat. Contact your veterinarian the same day if your kitten or young cat: - Stops eating for more than 24 hours. - Has repeated vomiting or diarrhea. - Seems painful, lame, or unwilling to move. - Has a swollen or hot joint. - Is losing weight. Go to an emergency clinic now if your cat: - Is struggling to breathe. - Has a bloated, painful abdomen. - Cannot urinate, or is straining in the litter box with no urine produced. - Collapses or has a seizure. - Has pale gums or is bleeding. Schedule a routine visit if: - Your cat is still visibly growing after 2 years. - Your cat is much smaller than expected for its breed. - You are unsure whether your cat's weight is appropriate. - You want to plan neuter timing. For general lifespan questions as your cat moves out of the growth phase, see [How Long Do Cats Live? Indoor, Outdoor and Senior Cat Lifespan Guide](/knowledge/veterinary-medicine/preventive-care/how-long-do-cats-live-lifespan-guide). ## Frequently Asked Questions ### Do all cats stop growing at 1 year? No, 1 year is the typical finish for most mixed-breed and medium cats, but large breeds often keep growing until 18 to 24 months. A few giant breeds may take up to 3 years. Your cat's breed and sex are the best clues. ### Is my cat full grown if it still looks skinny? Looking lean is not the same as being underweight. A young cat that is still filling out may look lanky for a few months. Ask your veterinarian to score your cat's body condition at the next visit. ### Does neutering make cats grow bigger? Neutering delays growth plate closure, so neutered cats can end up slightly longer in the leg bones than intact cats of the same breed and sex. This is a normal effect and not a health concern. ### Can a cat keep growing after 2 years? It is uncommon, but some large breed males may still add a small amount of body condition after 2 years. Visible bone growth after 2 years is unusual and should be checked by a veterinarian. ### Does food affect how big my cat gets? Nutrition affects whether a cat reaches its genetic potential, but it does not make a small cat large. Feed a complete kitten diet and follow your veterinarian's guidance on portions and switching to adult food. ## Related Articles - [Cat Neuter Age](/knowledge/veterinary-medicine/preventive-care/cat-neuter-age) - [How Long Can A Cat Go Without Peeing Or Pooping](/knowledge/veterinary-medicine/symptom-guides/how-long-can-a-cat-go-without-peeing-or-pooping) - [How Long To Introduce New Cat To Old Cat](/knowledge/veterinary-medicine/clinical-methods/how-long-to-introduce-new-cat-to-old-cat) - [How Long Do Cats Live? Indoor, Outdoor and Senior Cat Lifespan Guide](/knowledge/veterinary-medicine/preventive-care/how-long-do-cats-live-lifespan-guide) - [How Long Can A House Cat Go Without Peeing](/knowledge/veterinary-medicine/symptom-guides/how-long-can-a-house-cat-go-without-peeing) - [Cat Not Eating But Acting Normal: How Long Can You Wait?](/knowledge/veterinary-medicine/vet-visit-decisions/cat-not-eating-but-acting-normal) ## References 1. [The effect of prepuberal and postpuberal gonadectomy on radial physeal closure in male and female domestic cats](https://pubmed.ncbi.nlm.nih.gov/9238769/). Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association, 1997. 2. [Effect of neutering and breed on femoral and tibial physeal closure times in male and female domestic cats](https://pubmed.ncbi.nlm.nih.gov/24027051/). Journal of feline medicine and surgery, 2014. 3. [Osteoporotic risk and physeal closure in prepubertal ovariohysterectomized cats](https://pubmed.ncbi.nlm.nih.gov/26386680/). Animal reproduction science, 2015. ## Further Reading - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners) - [Cornell Feline Health Center: Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)