Shelter or rescue? List your pets free →

Cat Feeding Calculator

Work out your cat's daily energy from weight, life stage and whether they are desexed, then turn it into grams using the kilojoule or calorie figure on your own food's label. The formula is the one in the MSD Veterinary Manual, cross-checked against WSAVA's chart for adult cats.

Free · No signup · Works with any food
Author: LocalPetFinder Team

The short answer

A cat's daily energy is its resting requirement (70 × weight in kg0.75) multiplied by a life-stage factor: 1.2 for a desexed adult, 1.4 for an entire adult, 1 for an adult prone to obesity and 2.5 for a kitten. A 4 kg desexed adult needs about 238 kcal (about 996 kJ) a day. Convert that to grams with the figure on your own food, split it into several small meals, and let body condition settle the final amount. The result is an estimate; check with your vet.

🐟

Cat Feeding Calculator

How much should I feed my cat?

0.5 kg10 kg
Life stage

Desexing changes the factor from 1.4 to 1.2, so a desexed adult needs about 14% less energy than an entire cat of the same weight.

3,500 kcal per kg is only an example. Replace it with the figure on your food's label. Wet food is mostly water, so it carries far less energy per kg than dry; if you feed both, work out each share separately.

~68 g/day
of your food
about 238 kcal (996 kJ) a day

Split it into several small meals, ideally at least 4 to 5 a day, as the RSPCA advises.

Working it out: resting energy = 70 × 4.00.75 = 198 kcal, × 1.2 for this life stage = 238 kcal a day.

Cross-check: WSAVA's chart for an average healthy adult cat in ideal body condition gives 225 to 250 kcal a day at 4.0 kg.

Treats, if any, should stay under 10% of the day, here about 23 kcal, and come out of the total above (WSAVA).

Check body condition every few weeks: you should feel the ribs with a slight covering of fat and see a waist from above. Adjust if the weight drifts.

A starting point only, from the formula in the MSD Veterinary Manual. Follow your food's label and your vet, who sets the right amount for your cat, especially for weight loss or any health condition.

How the calculator works

The MSD Veterinary Manual (reviewed by a board-certified veterinary nutritionist in 2023) gives resting energy as 70 × body weight in kg to the power of 0.75, and multiplies it by a factor from its table of daily maintenance energy requirements for cats:

The manual says any calculation is only a starting point, and that animals of the same weight can need as much as 30% more or less energy than each other. As a cross-check, the WSAVA calorie chart for an average healthy adult cat (updated July 2020) gives 225 to 250 kcal a day at 4 kg and 250 to 290 kcal at 5 kg. The calculator shows the WSAVA range next to your result for adults from 1 to 7 kg.

Australian labels often give energy in kilojoules. One kilocalorie is 4.184 kJ, and the calculator converts either way.

The desexing step most feeding guides skip

On the MSD factors, a desexed adult cat needs 1.2 times its resting energy against 1.4 for an entire cat, about 14% less at the same weight. The RSPCA Australia Knowledgebase says there is a documented increase in risk of obesity in desexed cats, particularly male cats, and that a desexed cat should eat an appropriate diet, including the amount of food, and exercise enough to keep a healthy body condition.

The same page still recommends desexing. The practical answer is to recalculate the portion after the operation, rather than carrying on with the old amount.

Wet food, dry food and meals

The RSPCA Knowledgebase says a balance of wet and dry food is preferable, and that moist foods such as canned food or pouches help ensure adequate water intake and support a healthy urinary tract. Fresh water should always be available, and it advises against giving milk, which can upset the stomach.

The MSD Veterinary Manual puts canned foods at 60% to over 87% moisture and dry foods at 3% to 11%, so a gram of wet food carries much less energy than a gram of dry. If you feed both, decide what share of the day's energy each provides, then convert each with its own label.

On timing, the RSPCA says adult cats should ideally be offered food at least 4 to 5 times a day and kittens at least 4 times, and that puzzle feeders and varied feeding spots make meals last longer and may help prevent obesity. WSAVA says treats should make up less than 10% of a cat's daily calories, so take them out of the total rather than adding them on top.

Feeding for weight loss: a job for your vet

Cats must not be crash-dieted. The University of Illinois College of Veterinary Medicine says overweight or obese cats have a greater chance of developing hepatic lipidosis, which can be fatal, and that the most important thing to watch for is a cat not eating for multiple days. If a cat stops eating, see a vet promptly.

This calculator does not produce a weight-loss ration. Cats Protection says not to starve a cat or drastically reduce its food in one go, and the MSD Veterinary Manual explains that feeding less of an ordinary maintenance food also reduces every other nutrient. Ask your vet for a target weight, a food and a daily amount. To see where your cat sits now, use the is my cat overweight checker.

More for cat owners

The cat age calculator converts your cat's age into human years and shows its life stage, and our cost of owning a cat in Australia guide covers food alongside everything else. If you are still choosing, try the what cat breed am I quiz, read our guide to adopting a cat in Australia, or browse adoptable cats in Sydney, Melbourne and Brisbane. The dog version of this tool is the dog feeding calculator.

Frequently asked questions

Tap a question to expand

How much should I feed my cat per day?▼
It depends on weight, life stage and whether your cat is desexed. The calculator uses the MSD Veterinary Manual formula: resting energy = 70 × body weight in kg to the power of 0.75, multiplied by 1.2 for a desexed adult, 1.4 for an adult that is not desexed and 1 for one prone to obesity. A 4 kg desexed adult works out at about 238 kcal (about 996 kJ) a day, inside the 225 to 250 kcal range on WSAVA’s chart for an average healthy 4 kg adult. Divide by the energy figure on your food’s label to get grams, then let body condition and your vet fine-tune it.
Why does desexing change how much I feed?▼
The MSD Veterinary Manual uses a factor of 1.2 for a neutered adult cat against 1.4 for an intact one, so a desexed cat needs about 14% less energy at the same weight. The RSPCA Australia Knowledgebase says there is a documented increase in risk of obesity in desexed cats, particularly males, and that a desexed cat should eat an appropriate amount and exercise enough to stay in healthy body condition. Re-measure the portion after the operation rather than carrying on as before.
Should I feed wet food, dry food, or both?▼
The RSPCA Knowledgebase says a balance of wet and dry food is preferable, and that moist foods such as canned food or pouches help ensure adequate water intake and support a healthy urinary tract. The MSD Veterinary Manual puts canned foods at 60% to over 87% moisture and dry foods at 3% to 11%. Because wet food is mostly water, it has far less energy per kilogram, so read each label and split the daily energy between the two.
How many times a day should a cat eat?▼
More often than many people think. The RSPCA Knowledgebase says adult cats should ideally be offered food at least 4 to 5 times a day, because smaller, frequent meals have been associated with better urinary tract health and match their natural feeding pattern, and kittens at least 4 times a day. The MSD Veterinary Manual notes cats graze, eating as many as 18 small meals a day. Divide the daily amount across the meals rather than adding food, and puzzle feeders, which the RSPCA suggests, make each meal last longer.
How do I feed a cat that needs to lose weight?▼
With your vet, not with this calculator. The MSD Veterinary Manual explains that feeding less of an ordinary maintenance food also cuts every other nutrient, which is why vets often use a less energy-dense diet. Cats Protection says not to starve a cat or drastically cut its food in one go, and the University of Illinois College of Veterinary Medicine says overweight cats have a greater chance of hepatic lipidosis, which can be fatal, and that the key warning sign is a cat not eating for multiple days. Ask your vet for a target weight and a daily amount.
How much should I feed a kitten?▼
Much more for their size than an adult. The MSD Veterinary Manual uses 2.5 times resting energy for healthy kittens and notes they can alternatively be fed free choice. The RSPCA Knowledgebase says kittens should be offered a complete kitten food at least 4 times a day, starting with wet kitten food and introducing dry as they grow, and that your vet can weigh your kitten and check its body condition. Recalculate as an adult and again after desexing.
Why does the amount on the food label differ from this?▼
Both are starting points. The MSD Veterinary Manual says any formula should be treated as a starting point and that an animal may need as much as 30% more or less energy than another of the same weight. It also says that if a cat needs 10% to 30% less food than the label recommends to stay at an ideal weight, a less energy-dense diet may suit better. Watch your cat’s body condition over a few weeks and let your vet settle any gap.
Do cats need meat, or can they be vegetarian?▼
Cats need meat-based nutrition. The RSPCA Knowledgebase describes cats as obligate or true carnivores that cannot be healthy or survive without the nutrients in a prey-based diet, and says never to feed them dog food because it is deficient in taurine, which cats can only get from food. The MSD Veterinary Manual adds that, unlike dogs, cats need dietary sources of vitamin A, arachidonic acid and taurine. Feed a complete and balanced cat food and talk to your vet before any unusual diet.

General information only, not veterinary advice. Sources: MSD Veterinary Manual, “Nutritional Requirements of Small Animals” and “Daily Maintenance Energy Requirements for Dogs and Cats” (S. L. Sanderson, 2023, updated 2024); WSAVA “Calorie Needs for an Average Healthy Adult Cat in Ideal Body Condition” (2020) and “Feeding treats to your cat” (2025); RSPCA Australia Knowledgebase, “What should I feed my cat?” and “What should I feed my kitten?” (2025) and “Why should I have my cat desexed?”; University of Illinois College of Veterinary Medicine; Cats Protection.