How much food should a Cornish Rex eat? It depends on weight, age, and how active the cat is — not on the breed name alone. A Cornish Rex is typically 3–5 kg (6.6–11.0 lb) as an adult, so daily food ranges from roughly 190 to 280 calories a day for a typical neutered indoor adult, and more for an active, outdoor, or intact cat. This guide works it out properly: the resting energy requirement (RER) formula vets use, the calorie table for Cornish Rexs at different weights, grams per day, feeding by life stage, and the mistakes that most often lead to an overweight Cornish Rex.
Cornish Rexs are commonly described as active, intelligent, playful. A calm indoor cat burns far less than an active one that plays hard and patrols a garden, so two Cornish Rexs of the same weight can need quite different amounts of food — use the tables below as a starting point, then adjust by body condition: you should be able to feel the ribs easily under a thin layer of fat and see a waist from above and from the side.
How many calories does a Cornish Rex need?
Veterinary nutritionists start with the resting energy requirement, or RER — the calories a cat burns at rest in a neutral temperature, doing nothing at all. The formula is:
RER = 70 × (body weight in kg)^0.75
For a Cornish Rex at the middle of the breed's typical weight range, about 4 kg, the RER is 70 × 4^0.75 ≈ 200 calories a day. Daily needs are then the RER multiplied by a factor for life stage and activity: about 1.2 for a typical neutered indoor adult, about 1.4 for an intact adult, about 1.4–1.6 for an active or outdoor cat, about 2.5 for a kitten, and about 1.1–1.4 for a senior. So a typical neutered indoor Cornish Rex of 4 kg needs about 240 calories a day, while the same cat living an active outdoor life could need about 295.
These factors are the standard ones used in veterinary nutrition, but they are still starting points. A Cornish Rex that sleeps most of the day indoors needs less than one that hunts, climbs, and plays for hours, and a cat that has been neutered typically needs about 10–20% fewer calories than before. The right amount is the one that keeps weight steady inside 3–5 kg: weigh the cat monthly, and if weight drifts up, cut food by about 10% and re-weigh in a month rather than changing everything at once.
Cornish Rex daily calories by weight
| Body weight | Neutered indoor adult (×1.2) | Intact adult (×1.4) | Active / outdoor (×1.5) | Weight loss (×0.9) |
|---|---|---|---|---|
| 3 kg | 190 | 225 | 240 | 145 |
| 4 kg | 240 | 275 | 295 | 180 |
| 5 kg | 280 | 330 | 350 | 210 |
Use the row nearest your cat's weight, then pick the column that matches the cat's life. A kitten's row is different — see the life-stage section below — and a pregnant or nursing Cornish Rex needs considerably more, which your vet should set individually. If your cat is between two rows, take the lower figure first: it is easier to add food to a cat that is losing weight than to take weight off a cat that has gained it, and Cornish Rexs gain weight easily when food is guessed rather than measured.
Note that calories are the real target and grams are only a translation. Different foods have very different calorie densities, so always check the kcal per 100 g on your own bag or tin and work from that. The grams figures below assume a typical dry food at around 350 kcal per 100 g — a common figure, but your food may differ, and the packet's number always wins over this guide's.
How much food in grams per day
| Body weight | Calories (neutered indoor adult) | Grams of dry food per day |
|---|---|---|
| 3 kg | 190 kcal | 54 g |
| 4 kg | 240 kcal | 69 g |
| 5 kg | 280 kcal | 80 g |
Split the daily amount into two meals for an adult Cornish Rex — morning and evening — or use a puzzle feeder so the cat works for its food, which slows eating and adds mental stimulation. If you feed wet food, use the tin's kcal figure to convert: a typical wet food is around 70–100 kcal per 100 g, so a 4 kg Cornish Rex needing 240 calories would need roughly 282 g of wet food a day. Mixed feeding is fine as long as the total calories add up — the common mistake is to give a full measure of dry food plus a full pouch of wet food, which roughly doubles the ration.
Measure food with scales, not a scoop or a handful. A "scoop" in one house can be half as much again as a scoop in another, and that hidden extra is often the whole reason a Cornish Rex is overweight. Weigh the daily amount once, note what it looks like in your scoop, and use that scoop every time. Treats count too: they should stay under 10% of daily calories, which for a 4 kg Cornish Rex is under about 25 calories of treats a day — a few small treats, not a handful.
Feeding a Cornish Rex by life stage
Kitten (up to about 12 months). A Cornish Rex kitten grows fast and needs a kitten food — one labelled complete and balanced for kittens — fed in three to four meals a day until about six months, then two meals a day. Use the ×2.5 factor on the RER at the kitten's current weight, and re-weigh every two weeks, because the amount changes quickly as the kitten grows. Do not overfeed a kitten: excess weight in kittenhood sets up weight problems for life.
Adult (about 1 to 10 years). Two meals a day, a complete adult food, measured amounts, and a monthly weigh-in. This is the stage where weight most often creeps up, because the cat has stopped growing but the owner keeps feeding kitten amounts, or because the cat becomes indoor-only while food stays the same. If your Cornish Rex is neutered, expect to cut food by roughly 10–20% after the operation and watch the waistline for the next few months.
Senior (from about 11 years). Older Cornish Rexs often need fewer calories — the ×1.1–1.4 range — because they move less, but they still need good protein to hold muscle. A senior food, or an adult food fed in a smaller amount with your vet's agreement, is usually right. Some seniors develop kidney or other health issues that change the diet entirely, which is a vet decision, not a food-brand decision. Cornish Rexs may be prone to obesity and dental disease, so mention any change in appetite, thirst, or weight to your vet promptly rather than adjusting food on your own.
Common feeding mistakes with Cornish Rexs
The most common mistake is free-feeding — leaving a full bowl of dry food down all day. It makes it impossible to know how much the cat has eaten, it hides appetite changes that are often the first sign of illness, and it is the fastest route to an overweight Cornish Rex. The second is feeding by the packet's chart alone: packet charts are generous, because they are written for active cats and rounded up, so treat them as a maximum, not a target. The third is treat creep: a treat here, a piece of cheese there, and the cat's daily calories rise by a quarter without anyone noticing. The fourth is milk: most adult cats cannot digest lactose well, and milk is not a substitute for water — fresh water should always be available. The fifth is switching foods suddenly, which upsets digestion — change foods gradually over a week, mixing the old and new in increasing proportions.
Foods a Cornish Rex should never eat
Some everyday foods are toxic to cats and should never be given, in any amount: onions, garlic, leeks, and chives; chocolate and cocoa; grapes and raisins; xylitol (birch sugar, found in some sugar-free gum, sweets, and peanut butter); alcohol; and raw fish or raw meat that has not been handled safely. Lilies are also highly toxic to cats — even the pollen — so keep lilies out of a house with a cat. If your Cornish Rex eats any of these, call your vet or an animal poison line straight away — do not wait for symptoms and do not try to treat it at home. Keep a note of what was eaten, how much, and when, because the vet will ask.
Choosing a food for a Cornish Rex
Look for a food labelled "complete and balanced" for the cat's life stage, from a manufacturer that employs veterinary nutritionists and runs feeding trials — the label and the company's transparency matter more than the marketing on the front of the bag. Price is not a reliable guide to quality, and neither is the ingredient list alone: what matters is the nutrient profile and whether the food suits your individual cat's digestion, coat, weight, and energy. Cats are obligate carnivores, so their food must contain animal protein and nutrients such as taurine and arachidonic acid that cats cannot make themselves — a dog food, or a vegetarian diet, is not safe for a cat. If your Cornish Rex has a health condition, ask your vet or a veterinary nutritionist before choosing a special diet — therapeutic diets are medicines in food form and should not be chosen by guesswork.
For related reading, see the Cornish Rex age guide, the Cornish Rex lifespan guide, the cat food calculator, the cat breeds hub, the Exotic Shorthair food guide, the cat age in human years chart.
Frequently asked questions
How much food should a Cornish Rex eat per day?
A typical neutered indoor adult Cornish Rex of 4 kg needs about 240 calories a day, which is roughly 69 g of a typical dry food at 350 kcal per 100 g. At the ends of the breed's typical weight range the figure is about 190 calories at 3 kg and about 280 at 5 kg. Adjust by body condition and your vet's advice — active, intact, kitten, and senior cats all differ.
How many times a day should I feed a Cornish Rex?
Two meals a day for an adult Cornish Rex, morning and evening, or the same daily amount in a puzzle feeder. Kittens need three to four meals a day until about six months, then two. Free-feeding — leaving food down all day — makes portion control and appetite monitoring much harder.
How many calories does a Cornish Rex kitten need?
Use the RER formula with a factor of about 2.5, applied to the kitten's current weight and re-checked every two weeks as the kitten grows. A kitten food labelled complete and balanced is the right base, and your vet should check growth against the expected adult weight of 3–5 kg.
How do I know if my Cornish Rex is overweight?
Feel the ribs: you should feel them easily under a thin layer of fat without pressing hard. Look from above for a visible waist behind the ribs, and from the side for a tummy tuck. If you cannot feel the ribs or there is no waist, the cat is probably overweight — cut food by about 10%, keep treats under 10% of daily calories, and ask your vet to set a target weight. The cat ideal weight calculator gives a starting range.
Can a Cornish Rex drink milk?
Most adult cats cannot digest lactose well, so milk often causes an upset stomach and adds calories the cat does not need. Fresh water is what a cat needs — offer it in a clean bowl, away from the litter tray, and consider a water fountain if your Cornish Rex prefers running water. Kittens should have their mother's milk or a vet-recommended kitten milk replacer, never cow's milk.
What foods are toxic to a Cornish Rex?
Onions and garlic, chocolate, grapes and raisins, xylitol, alcohol, and lilies — even lily pollen — are all dangerous for cats. If your Cornish Rex eats any of them, call your vet or an animal poison line immediately and tell them what was eaten, how much, and when.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.