Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

How Big Does a Cornish Rex Get? Vet Reviewed Weight & Growth Chart

Share

close up of a cornish rex with green eyes

The Cornish Rex is a cat breed that is extremely distinct. Like other animals with the rex gene, they are covered in a layer of downy, soft, curly, or wavy fur. They have long, slender bodies and narrow faces.

If you were interested in the Cornish Rex, you might wonder exactly how large these cats get. A full grown Cornish Rex is expected to weigh 6-10 pounds and measure 8-12 inches. In this article, we will go over their particular growth patterns and other details about what to expect when you own one of these fascinating felines.

divider 1 paws

Cornish Rex Overview

The Cornish Rex is a genetic anomaly. In Cornwall, England, during the 1950s, a kitten was born that would be the platform for all Cornish Rex that exist today. This kitty was very different from his brothers and sisters, having a downy, curly coat.

Luckily, Nina Essenmore was the one who found the kitten. She was very knowledgeable about the rex gene chain because she raised rex rabbits. She worked diligently alongside professionals to develop the Cornish Rex breed, and we’re certainly glad she did!

The Cornish Rex is one of the most unique-looking felines to exist today. Plus, it has a sound temperament and excellent companionship potential.

Cornish rex cat sitting on the grass
Image Credit: Rita_Kochmarjova, Shutterstock

Cornish Rex Size and Growth Chart

The Cornish Rex is a medium sized breed that looks rather large due to their height, which is between 8-12 inches. However, these cats are incredibly light on their feet, giving them a lanky appearance. Males tend to be larger than females.

Age Weight
Newborn 1.8–5.3 ounces
2 Weeks 5.3–8.8 ounces
3 Weeks 12.3–15.9 ounces
4 to 8 weeks 1.4–2 pounds
9 to 12 weeks 3–3.5 pounds
12-16 weeks 4–4.5 pounds
16-20 weeks 5–5.5 pounds
6 months 6–6.5 pounds
12 months 6-10 pounds

When Does a Cornish Rex Stop Growing?

This particular breed stops growing between the ages of 9 and 12 months of age. Certain factors, such as genetics, diet, and environment, play a role in when growth will end.

divider 1 paws

Factors Affecting the Size of Cornish Rex

Several factors can affect the size of your Cornish Rex. Here are some things that can determine ultimate size.

Cornish Rex kitten
Image Credit: Elena Loginova, Shutterstock

Diet

A high quality diet is vital, especially during your kitten’s growing months. They need proper nutrition to nourish their growing bones, muscles, and organs as they develop. If a kitten is malnourished, it can cause a reduction in growth.

Malnutrition as a kitten could make them much smaller as adults than they would have been had they had the appropriate care.

On the other hand, if you give your Cornish Rex far too much to eat regularly, the extra calories could quickly lead to becoming overweight, which may snowball into obesity and a whirlwind of other health issues. If you have any questions on the amount you should feed a Cornish Rex kitten, speak to a vet.

Need veterinary advice but can't get to the clinic? Catster recommends PangoVet, our online veterinary service. Talk to a vet online and get the answers and advice you need for your cat without having to leave your living room — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

Genetics

Genetics plays a very significant role in ultimate size. For example, if you have two Cornish Rex parents on the smaller end of the scale, they will likely produce smaller kittens.

If one of the parents is particularly small for the breed, and the other is quite large, you could have a random mix of sizes among kittens of the litter. Oppositely, it goes without saying that if both Cornish Rex parents are reasonably large for the breed, their kittens should also be larger when fully grown.

Health Conditions

Certain health conditions can cause delayed growth in cats. For example, kittens that are very sick or weaned early from their mother may grow at a slower rate than healthy kittens. There are even some rare genetic issues that can result in a smaller size, such as dwarfism.

divider 1 paws

Ideal Diet for Maintaining a Healthy Weight

A Cornish Rex’s weight can be difficult to manage, especially given their small size. To keep them at a healthy weight, especially after a spay or neuter surgery, here are some tips on how to manage.

Portion Control

You should always demonstrate portion control when dishing out your cat’s meals. Each bag will have serving recommendations based on your cat’s current weight and weight loss goals (if any).

Giving them the correct portions will help ensure they are getting the appropriate amount of nutrition and calories at every meal. They are a guideline however and should be used as a starting point. Some individuals will need more or less than the guidelines to keep in a healthy weight range. Also, this will help you monitor their appetite.

Exercise

It may be difficult to exercise a cat, but exercise plays a large role in overall health, including maintaining a healthy weight. You may get your cat to exercise by encouraging play with interactive toys, cat trees for climbing, or outside time if possible.

Regularly Attend Vet Visits

Taking your cat to the vet regularly will really help with weight management. Your vet will be the first to tell you if your cat should go on a diet or if they need more calories. Also, dietary needs can change based on a change in health status or stage of life.

vet checking up the cat
Image Credit: Maria Sbytova, Shutterstock

How to Measure Your Cornish Rex

Measuring your cat is important for quite a few reasons. First of all, it will help you know if their growth is on track. However, knowing how to measure your cat could be nice for other reasons, such as purchasing cat-specific products.

For example, if you’re buying a cat carrier, you want to know that it’s a suitable size for your feline companion. Or, maybe, you want to buy a harness and leash to take your cat on adventures. Their appropriate measurements will ensure a proper fit and avoid lengthy returns or exchanges.

  1. Use a flexible measuring tape.
  2. Measure the neck around the part where the collar would naturally sit.
  3. Measure the chest behind the shoulder and armpits and around the back to check the broadest circumference.
  4. For length, measure from the neck’s base to the tail’s base.
  5. For height, measure from the ground to the top of the shoulder.
  6. For weight, place your cat directly on a scale. Alternatively, you can weigh yourself, then weigh yourself holding your cat, and subtract your weight from the total weight to find your cat’s weight.
You are free to use this image but we do require you to link back to Catster.com for credit

divider 1 paws

Conclusion

Now that you know what to expect from a Cornish Rex‘s growth, are you still interested in owning one of these fun-loving kitties? We’re sure you won’t be disappointed since these cats have lovely personalities and extraordinarily unique features.

Remember, if you want to purchase a Cornish Rex kitten, check for reputable breeders in your area. Most breeders will work under the approval of cat associations to ensure buyers receive a quality kitten.


Featured Image Credit: Jenni Ferreira, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Ask Dr. Paola – Help! My Momma Cat Is Very Thin! (May 18, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

The Cat Biting Mistakes Most Owners Make (And What Works Instead)

Cat bites sent more than 400,000 people to emergency rooms in the US each year.1 Not scratches. Bites. And the reason they’re so...

Do Cats Cause Schizophrenia? Scientists Find a Link – Here’s What It Means

Being a fierce advocate (and occasional recipient of) mental health support and awareness, the term ‘crazy’ is not one I like to fling...

One in 100 Cats Gets Diabetes – Here’s How to Catch It Early

One in every 100 cats develops diabetes.1 That’s not a rare, unlucky condition reserved for cats with obvious health problems. It’s common enough...

More related

Kitty Horoscope: April Belongs to the Fiery Aries Feline

If you have an Aries cat, you know it! There’s really no denying these traits. An Aries is always going to be strong,...

Is Human Lotion Safe for Cats? Vet-Reviewed Safety & Toxicity Explained 

If your cat has dry skin, you may be wondering if you can apply a bit of your own lotion to ease their...

How to Keep Litter Boxes from Smelling: 12 Vet Approved Tips

A common goal among cat owners is keeping the litter box smell to a minimum. This can pose a bit of a challenge,...

What Colors Do Cats Like? Vet-Reviewed Facts & Preferences Revealed

Ever wondered what colors cats like the most? The answer isn’t so simple. The way that cats view and perceive the world is...

Keep reading

Can Cats Eat Gingerbread? Vet-Approved Facts & FAQ

Gingerbread is a tasty holiday treat that people around the world enjoy. The sweetness and the zing of ginger produce a unique flavor profile. Unsurprisingly, you might want to share some gingerbread with your cat! Not only does gingerbread taste...

Can Cats Eat Gingerbread

Why Do Cats Pee When Scared? 2 Reasons for This Behavior

If you’re a cat owner, chances are that you don’t see your cat pee anywhere but the litter box. Sometimes, though, you may notice that cat urine is on the floor or the couch, and your cat is nowhere to...

Cat Owner Hold Cat Car Scared

Why is My Cat Breathing So Hard? 9 Vet-Approved Reasons & What to Do

Just like dogs, cats may breathe heavily and pant in certain circumstances. Because this behavior is much rarer in cats than in dogs, it is usually something to be worried about, especially if it persists for prolonged periods. Panting is...

close up white cat breathing

10 Best Dry Cat Foods in 2026 – Reviews & Top Picks

Deciding on the best dry cat food for your feline friend can be a bit of a challenge, especially given how many options are available. From flavor to nutritional content, every little detail matters in ensuring that your cat gets...

siamese kitten eating from a stainless bowl

Is Dieffenbachia Toxic to Cats? Vet-Reviewed Houseplants Examined

Dieffenbachia is a common house plant favored by many because it is tolerant of shade, so it can grow well in a houseplant collection. Plus, it comes in a good variety of appearances. While it is a popular houseplant, it...

Catster_Is Dieffenbachia Toxic to Cats

Signs a Cat is Dying: 11 Vet-Verified Changes to Look For

It’s the moment that no cat owner wants to contemplate, but as our feline friends get older or maybe develop an illness, their deteriorating health can begin to show signs your cat is dying. As difficult as this time can...

tired or sick cat

How to Stop Your Cat from Over-Grooming: Vet Answer & Advice

Cats are fastidious self-groomers, which is their trademark trait that begins from an early age. Your cat will tend to clean their fur by licking themselves for a large part of their waking hours. This makes it challenging to observe...

Chinchilla Persian Cat licking its paw

6 Reasons Your Cat May Attack You & How to Fix It

Your normally happy cat is staring intently outside at something, tail completely straight and ears back. You wonder what is bothering them, so you walk over to your cat and they suddenly lash out at you! Even worse is when...

man playing with cat in bed_Anna Kraynova_shutterstock

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.