What age do cats stop growing?
Article checked by a vet
Looking after a kitten is a special time for any pet owner, as they enrich our lives with mischief and love. Kittens have unique dietary needs and care requirements, and once a cat reaches adulthood, you will need to adjust their diet and routine. When do kittens become cats? Generally, most cats will reach their full size at around 12–18 months of age. However, this can vary significantly based on breed, genetics, diet, and health. In this article, we will explore everything you need to know about the life stages of cats, including when common cat breeds become fully grown, so you can be readily prepared for these life stage changes. Need some help determining how old your kitten or cat is? Check out our calculating cat years blog for more advice.
When are common cat breeds fully grown
There are many unique cat breeds, and they all mature at their own pace; however, each breed has average growth durations as detailed below.
At what age do Maine Coon cats stop growing? 3–5 years, however, individual growth can still vary.
At what age do Norwegian Forest cats stop growing? 2-4 years, however, individual growth can still vary.
At what age do Ragdoll cats stop growing? 2–3 years, however, individual growth can still vary.
At what age do Siamese cats stop growing? 12–18 months, however, individual growth can still vary.
At what age do British Shorthair cats stop growing? 12-18 months, however, individual growth can still vary.
At what age do Persian cats stop growing? 18–24 months, however, individual growth can still vary.
Life stages of cats
Kittens experience an incredibly rapid period of growth and development during their first few weeks of life. Kittens are born with their eyes and ears closed. They cannot walk yet, so they crawl on their tummies and rely on their developing sense of smell to find and feed from mum.
Ages of Kittens | Growth Milestones. |
|---|---|
2 weeks of age | By two weeks of age, your kitten’s eyes will have opened and they will be blue. This colour will begin to change as they get older. |
3 weeks of age | By 3 weeks of age, the kitten’s ear canal has fully opened. |
4 weeks of age | Before 4 weeks of age, kittens rely on their mother to stimulate them to excrete their waste. By 4 weeks of age, the kitten can now eliminate urine and faeces on their own, once this happens, it is time to start litter training!
Their needle sharp deciduous (milk teeth / baby teeth) are also starting to erupt through the gums.
Kittens are also starting to explore their surroundings a little wider away from mum and interact properly with their littermates.
Kittens will also start showing an interest in mum’s food and can now be weaned onto kitten food. |
8–12 weeks of age | Between 8–12 weeks of age, the kittens are old enough to have their vaccinations and can leave mum to go to their new home from 12 weeks of age. |
4 months | At 4 months old, the deciduous teeth start to fall out, and they are replaced by adult teeth. The kitten Will have a full set of adult teeth by about 7 months old. |
5 - 6 months | At 5–6 months, the kitten is old enough to be spayed or neutered. |
6 months of age | Kittens can start to look like adult cats by 6 months of age; However, they need nutritional support for optimum health and development during their entire growth phase, which lasts 12 months. We recommend that a kitten is fed specially tailored complete and balanced kitten food until they are 12 months of age, this is when they are considered an adult and can be fed adult cat food. |
Factors influencing cat size
When do kittens become adult cats? There are a multitude of different factors that impact how fast a cat will grow, for example, kittens need a huge amount of calories to reach their full size, so inadequate nutrition can impact them significantly at this stage. Most cats will reach their full size at around 12-18 months of age. However, this can vary based on breed, genetics, diet, and health.
Impact of neutering
Neutering your cat or kitten can also impact their body shape, particularly when this occurs before a cat reaches full maturity. Neutering a cat before they reach full maturity may result in slightly longer bones and a leaner physique overall. This is why knowing exactly when kittens become cats based on their breed is important. However, when neutered, cats are more likely to gain weight and are three times more likely to become obese. It’s important to remember if you have no intention of breeding your cat, you should have it neutered at the age your vet recommends. Leaving a cat entire puts their health at risk and means they are more likely to roam, be injured or have an unwanted litter.
Diet and nutrition
A complete and well-balanced diet tailored to meet the nutritional requirements of a kitten, is the key to maintaining healthy growth in kittens, no matter how old your kitten is. Kittens require more protein and calories than adult cats to support their rapid growth. Improper nutrition can lead to stunted growth or health issues, so knowing how often to feed your kitten is vital.
Gender differences
There are also some gender differences when it comes to size, males typically grow larger than females, with differences in weight, body mass and overall size. Males are also known to be longer than females and tend to develop distinct features like broader heads or thicker necks.
Measuring and monitoring growth
It’s a good idea to measure your cat to ensure they are growing at a steady pace, we suggest you do this once a month during their first year and record the measurements. You should always consult your veterinarian if their growth seems irregular or if the cat’s size deviates significantly from breed/age expectations.
- Height: measure from the floor to the base of their neck while your cat is on all fours.
- Weight: you can use pet scales or bathroom scales to weigh your cat, using treats might help keep them still.
- Body Length: we advise using string or a tape measure, starting from the cat's head and measuring to the base of the tail, following the spine.
Kitten weight and age correlation
A kitten’s age correlates with their weight, kittens tend to experience typical weight gain patterns in the first 6 months; however, growth can vary significantly based on many of the factors already discussed. As a benchmark, we can assume that a kitten will gain around 100 grams weekly. The average weight of a kitten at 9 weeks will therefore be about 900 grams.
- 2 weeks: 300g
- 4 weeks: 500g
- 8 weeks: 900g
- 12 weeks: 1700g
- 6 months: 4000g
What age do cats stop growing? Summary
In conclusion, most cats will reach their full size at around 12–18 months of age. However, this can vary significantly based on breed, genetics, diet, and health. Are you keen to learn more about your cat’s lifespan? Our Lifespan page has got you covered!
What age do cats stop growing? - FAQs
What age is a cat fully grown?
Most cats will reach full size at around 12–18 months of age. However, this can vary significantly based on breed, genetics, diet, and health. For example, Maine Coon cats become fully grown at 3–5 years of age.
Can you tell how big a cat will get?
Most cats will reach full size at around 12–18 months of age; however, this can vary significantly based on breed, genetics, diet, and health. For example, Maine Coon cats become fully grown at 3–5 years of age.
Do neutered cats grow bigger?
Neutering a cat before they reach full maturity may result in slightly longer bones and a leaner physique overall, this is why knowing exactly when kittens become cats based on their breed is important. However, when neutered cats are more likely to gain weight and three times more likely to become obese, so a complete and well-balanced diet and exercise routine are important.
How much do cats grow after 6 months?
Kittens experience the fastest rate of growth during the first 6 months of their lives, after this stage, growth will slow down and eventually stop once they reach maturity. Most cats will reach their full size at around 12–18 months of age; however, this can vary significantly based on breed, genetics, diet, and health.
How can I tell how old a kitten I found is?
Kittens tend to experience typical weight gain patterns in the first 6 months. However, growth can vary significantly based on many of the factors already discussed. As a benchmark, you can assume that a kitten will gain around 100 grams weekly. The average weight of a kitten at 9 weeks will therefore be about 900 grams. You should arrange a visit to your local vet to give the kitten a check-up, and they can also estimate how old your kitten is.
