How Much to Feed a Cat: The Arithmetic Behind the Bowl

Most indoor cats are fed by a number printed on the bag for a cat that does not exist: an active, unaltered, free-roaming cat from a formula that predates the modern spay-neuter clinic. The gap between that cat and the neutered five-year-old asleep on a windowsill for eighteen hours a day is enormous, and it is the single biggest reason feline obesity is now the most common nutritional disease vets see in an exam room.

The fix is not a stricter chart. It is a calorie target built for your actual cat, checked against what your hands can feel, and adjusted the slow way, because a cat that loses weight too fast can develop a liver disease that a dog on the same crash diet will not.

The number WSAVA actually publishes

Forget cups. A cat food's kcal per cup or per can varies by a wide margin between brands and formats, so cups are not a unit you can reason with until you have a calorie target to divide them into.

The World Small Animal Veterinary Association's Global Nutrition Committee publishes a reference table for daily calorie needs in a healthy adult cat, built from the 2006 National Research Council maintenance energy requirement equations. It gives two numbers, not one, because a lean cat and an obese-prone cat do not burn calories at the same rate per kilogram:

Weight	Lean adult (kcal/day)	Obese-prone adult (kcal/day)
4.5 kg (9.9 lb)	240	270
5.0 kg (11.0 lb)	250	290
5.5 kg (12.1 lb)	260	310
6.0 kg (13.2 lb)	265	330
6.5 kg (14.3 lb)	275	350

Read that gap carefully. At 5.5kg, WSAVA's range runs from 260 to 310 kcal a day, a fifty kcal spread for the identical weight. The obese-prone number sits higher because it reflects cats whose metabolism has already adapted to carrying extra fat, which burns calories less efficiently than lean tissue. Use the lean-adult figure as your starting point for a cat at a healthy weight, and only reach for the higher number if the cat is already overweight and you are trying to hold the line rather than lose it, which is a narrower use case than it sounds.

Once you have the daily kcal target, find the calorie content statement on the food, which every cat food sold in the US is required to carry, usually printed as kcal per kilogram and per can or cup. Divide your target by that figure and you have the actual daily amount, in the actual unit on the package, rather than a cup guessed from a chart built for a different cat. This is the same conversion this site walks through in more depth in how to read the guaranteed analysis on a cat food label, because the calorie statement and the protein guarantee sit on the same panel and get misread the same way.

Why the chart on the bag runs high

Package feeding guides are written to avoid underfeeding across the whole range of cats that might eat that food, so they lean generous by design, the same failure mode documented on the dog side of this calculation. Two feline-specific factors widen the gap further.

Neutering lowers a cat's energy requirement by a meaningful margin, commonly cited in the twenty to thirty percent range, and the vast majority of pet cats are neutered well before the chart's assumptions were written. Indoor confinement removes the calorie cost of hunting, territory patrol and outdoor thermoregulation that an outdoor cat pays for automatically. Stack both factors on a cat that spends most of the day within reach of a heated windowsill, and the printed guideline can run forty percent or more above what that specific cat needs to hold a stable, healthy weight.

The check that corrects the calculation

Body condition score is what actually confirms whether the number is right, and it takes less time than opening a can.

Run your hands along the ribcage with light pressure, the way you'd feel the back of your own hand. Ribs should be easy to find under a thin layer of fat, not padded over and not sticking out. Look down from above: there should be a visible waist behind the ribs, not a straight line from shoulders to hips. From the side, the belly should tuck up rather than hang or bulge.

The World Small Animal Veterinary Association's feline body condition chart uses the same nine-point scale as the canine one, with 4 to 5 as the target and each point above that corresponding to roughly ten to fifteen percent excess body weight. Cornell's Feline Health Center classifies anything above a 6.5 to 7 as overweight and 8 or 9 as obese or severely obese, and notes that obesity is now the most common nutritional disorder seen in cats. Score your cat monthly. If the calculated calorie target and the body condition score disagree, the cat is right and the arithmetic needs a different starting weight, not the other way round.

Weight loss, done at the pace a cat's liver tolerates

A safe rate of feline weight loss sits at roughly one to two percent of body weight per week, slower than most owners expect and slower than the equivalent target for a dog. For a 6kg cat, that is 60 to 120 grams a week, tracked on a kitchen scale that reads in tenths of a kilogram rather than a bathroom scale built for a human.

The practical version: calculate the target calorie intake for the cat's ideal weight rather than its current weight, using the lean-adult formula above, then introduce that reduction gradually over one to two weeks rather than cutting the bowl in half on day one. Weigh the food, not just eyeball the bowl, because a cat's daily ration at a reduced calorie target is often a strikingly small volume that looks like underfeeding until you have weighed it. Weigh the cat every two weeks. If two consecutive weigh-ins show no loss, tighten the target by another ten percent; if loss runs faster than two percent a week, ease it back. This is a project to run with a vet involved rather than alone, particularly for a cat that is more than twenty percent over ideal weight, because that is the population where hepatic lipidosis risk concentrates.

Kittens run on a completely different number

A growing kitten is the one case where the adult formulas above do not apply and where underfeeding, not overfeeding, is the real risk. Kittens need considerably more energy per kilogram of body weight than an adult cat doing the same activity, because growth itself costs calories on top of maintenance.

Cornell's Feline Health Center recommends feeding kittens more frequently than adults, at three meals a day until roughly six months old, rather than trying to hit a daily total in one or two sittings the way an adult cat can manage. Free feeding a growth-formula dry food is reasonable for most healthy kittens up to that age, provided the food carries an AAFCO adequacy statement for growth or all life stages, because that statement is what confirms the recipe was formulated for a kitten's protein, calcium and calorie needs rather than an adult's. Weigh a kitten weekly. Steady, unbroken weight gain is the sign to look for; a kitten that plateaus or loses weight needs a vet visit, since kittens have far less metabolic reserve than adult cats and decompensate faster.

What to do this week

Weigh your cat, or use its last recorded vet-visit weight if it is current. Look up the WSAVA lean-adult figure for that weight, or calculate 100 x weight in kg to the power of 0.67 directly. Find the kcal per kilogram or per can on the food currently in the cupboard and divide the target by it to get an actual daily amount in a unit you can measure. Score body condition with your hands. If the cat is a clean 4 or 5, the number you calculated is very likely close to right, and the job is just to keep measuring rather than free-pouring from here. If the cat is overweight, use the ideal-weight version of the calculation and start the one-to-two-percent-a-week plan, with a vet in the loop if the gap is large. From there, what's actually in the bowl and how the wet-versus-dry decision affects it become the next questions worth answering, and turning a portion of that measured ration into a puzzle feeder instead of a bowl is one of the few free ways to make the same calories do more work for a cat that is used to getting them in thirty seconds flat.

Questions people actually ask

How many calories does my average indoor cat need?

For a typical neutered adult cat at a healthy weight, the WSAVA reference table gives roughly 100 kcal times bodyweight in kilograms to the power of 0.67. A 5kg cat lands around 250 kcal a day. That is a starting point to check against body condition, not a fixed target.

Is it true cats shouldn't skip meals the way dogs can?

Yes, and it matters especially for an overweight cat. A cat mobilising fat stores faster than the liver can process them can develop hepatic lipidosis, a serious liver disease, within days of reduced intake. A cat that stops eating for over 24 hours needs veterinary attention.

How fast is it safe for a cat to lose weight?

One to two percent of body weight per week is the standard target. Faster than that raises the risk of hepatic lipidosis. A 6kg cat losing at the safe rate takes several months to reach a healthy weight, which is normal and not a sign the plan is failing.

Should I free-feed my cat or measure meals?

Measured meals, weighed rather than scooped, are the only reliable way to hit a calorie target. Free feeding dry food works for a small number of cats with genuinely good self-regulation, but most cats fed this way drift toward overweight over time, which is part of why feline obesity is now so common.

My kitten seems hungry all the time. Is that normal?

Largely yes. Growing kittens need far more energy per kilogram than adult cats and are commonly fed free-choice or three times a day on a growth-formula food up to about six months old. Track weekly weight gain rather than judging by appetite alone, and see a vet if gain plateaus or reverses.

Sources

• WSAVA Global Nutrition Committee: Calorie Needs for an Average Healthy Adult Cat
• WSAVA Global Nutrition Committee: Body Condition Score chart for cats
• Cornell Feline Health Center: Obesity
• Cornell Feline Health Center: Hepatic Lipidosis
• Cornell Feline Health Center: How often should you feed your cat
• AAFCO: reading pet food labels, including the calorie content statement