Cat Food Portion Calculator

The fields are labelled for cups, but the arithmetic works for any unit with a calorie count. For canned food, type the kcal per can into the calories field and the can's weight in grams into the grams field. The "cups" in the result then read as cans.

For the 10 lb neutered cat eating 85 g (3 oz) cans labelled at 80 kcal each, fed twice a day, the panel shows RER 218 kcal, MER 261 kcal, a daily portion of 3.26 cans (277 g) and 1.63 cans (139 g) per feeding. The 80 kcal is an example; use the calorie statement printed on your own cans, which varies widely between recipes.

Mixing wet and dry is a matter of splitting the calories. To give half of the 261 kcal from each, feed about 1.63 cans of the wet food and 0.37 cups (43 g) of the 350 kcal/cup kibble. Run the calculator once for each food and halve both results.

Weight in kg = lb × 0.45359237.

RER = 70 × kg^0.75 kcal a day.

MER = RER × the feline factor. These come from Box 1 of the AAHA 2021 Nutrition and Weight Management Guidelines, which lists them for cats as 1.2–1.4 neutered/spayed adult, 1.4–1.6 intact adult, 1.0 inactive or obese prone, 0.8 weight loss and 2.5 growth. This calculator uses the lower end of each range.

That weight-loss figure is worth pausing on, because it is the one most often quoted wrongly. The feline weight-loss factor is 0.8, not 1.0. In the AAHA table 1.0 is the *canine* weight-loss row and the feline *inactive/obese-prone* row; feeding an overweight cat at 1.0 is feeding it 25% more than the guideline intends, which is a common reason a diet stalls. This page used 1.0 until September 2026.

There is no weight-gain row in that table, so this calculator no longer offers one. An underweight cat needs a target from a vet, not a multiplier.

Daily portion = MER ÷ kcal per cup (or can); grams = portion × grams per cup (or can); each meal = daily amounts ÷ number of feedings.

Why the answer is only a start: the WSAVA Nutritional Assessment Guidelines (2011) note that a cat's real energy needs can differ from an estimate by about 50% in either direction, a wider band than for dogs. For the 10 lb cat, 261 kcal could turn out to be anywhere from about 131 to 392 kcal. Weigh your cat every couple of weeks and adjust.

A 14 lb neutered cat whose vet suggests a target of 11 lb eats a 320 kcal/cup dry food. Its present maintenance need is 336 kcal (1.05 cups). The Weight loss setting on its current 14 lb gives 224 kcal (0.70 cups, 81 g). Entering the 11 lb target weight with the same setting gives 187 kcal (0.58 cups, 67 g), the kind of figure a clinic plan built on ideal weight would start near.

AAHA also notes that recent data put mean intake for weight loss at 52 ± 4.9 kcal per kg of ideal body weight to the power 0.711 in cats. For an 11 lb (4.99 kg) ideal weight that is roughly 160 kcal a day, below what the 0.8 factor gives, which is a reminder that the factor is a starting point to be adjusted from rather than a target to hold.

The 2014 AAHA Weight Management Guidelines for Dogs and Cats give a desirable rate of loss for cats of 0.5 to 2% of body weight per week. For this cat that is 0.07 to 0.28 lb a week, so losing 3 lb takes at least about 11 weeks at the fastest recommended rate and about 21 weeks at 1% a week. A slower result is not a failed diet.

Change portions in steps rather than all at once, and weigh on the same scale every one to two weeks. If your cat refuses a new diet food, go back to what it will eat and call your vet; a cat that is not eating is more urgent than a cat that is not losing weight.

When a cat goes without enough food, its body moves fat into the liver faster than the liver can process it. The University of Illinois College of Veterinary Medicine warns that a cat going without food for a few days in a row risks hepatic lipidosis, and that overweight and obese cats have a greater chance of developing it. It can follow illness, stress, a house move, a new pet, or a diet food the cat will not touch.

That is why the cat weight-loss setting still supplies a full RER rather than a severe cut, why a diet should be paced within the AAHA range, and why appetite matters more than the scale. Watch for a cat that leaves meals, hides, or loses weight quickly, and treat a cat that has stopped eating as a reason to call the vet the same day.

Indoor or outdoor. The calculator has no separate indoor setting. For a typical indoor, neutered cat, the 1.2 neutered adult factor is the natural choice. For an intact cat, or a neutered cat that roams outdoors for hours, the 1.4 intact factor is the closest available option; confirm it with a few weeks of weigh-ins rather than assuming it.

Moisture changes the scoop, not the calories. Cornell University's Feline Health Center notes that canned cat food is at least 75% moisture while dry food holds 6 to 10% water. Weight for weight, canned food therefore delivers far fewer calories, which is why a cat can eat 277 g of cans but only 86 g of kibble for the same 261 kcal. Never swap one for the other by weight or volume; swap by calories.

Several cats, one bowl, no control. Free-feeding lets the boldest cat eat for two. Picture two cats in the same kitchen: the 10 lb neutered cat needs 261 kcal, while the 14 lb cat dieting towards 11 lb is on 234 kcal. The lighter cat needs more food than the heavier one, and a shared bowl cannot deliver that. Feed measured meals in separate rooms or at separate times, or use a microchip-activated feeder.

Treats. Cornell suggests keeping treats within 10 to 15% of a cat's daily calories, which for the 10 lb cat is roughly 26 to 39 kcal. Take them out of the day's total rather than adding them on top.

The calculator applies one fixed factor per category. It does not account for age beyond the kitten setting, lean muscle, pregnancy or nursing, or conditions that change energy needs, such as hyperthyroidism, diabetes and kidney disease. Its weight-loss setting uses whatever weight you enter, so it cannot tell a current weight from a target. Kittens change rapidly, and a kitten that has just been neutered can gain weight quickly on the kitten factor. Any cat that is losing weight, eating less, or under veterinary treatment needs a plan from a vet.

Households with a dog as well can use the Dog Food Portion Calculator, which covers working dogs, large-breed puppies and the canine factors. The Dog & Cat Age to Human Years Calculator helps judge when a kitten becomes an adult or an adult becomes a senior, both points at which the feeding category may need changing. The pet food portion guide explains the energy formulas in more depth, including why weight loss in cats needs extra care.