How Much Should You Feed Your Cat? A Portion Guide by Weight and Age

Feeding advice for cats often gets borrowed straight from dog food guides, with the word swapped and nothing else. But a cat isn't a smaller, fussier dog: it's an obligate carnivore built by evolution to hunt and eat many small meals through the day, not one or two large ones — and for the many cats who now spend their lives indoors without anything left to hunt, that mismatch is a real factor in why feline obesity is so common. This guide walks through how veterinary sources estimate a cat's calorie needs by weight and life stage, why meal pattern matters as much as the total amount, and where a general guide like this one reaches its limit versus your veterinarian and the feeding directions on your specific food.

The Science Behind Portion Sizes: Resting and Maintenance Energy

According to the Merck Veterinary Manual, a standard reference used in veterinary medicine, a cat's resting energy requirement (RER) — the calories needed just to maintain basic body function at rest — can be estimated with the same formula used across small animals:

RER = 70 × (body weight in kg) ^0.75

From there, maintenance energy requirement (MER) is estimated by multiplying RER by a factor that reflects life stage, reproductive status, and activity. For cats, the Merck Veterinary Manual's published multipliers are notably lower than the equivalent dog multipliers, reflecting cats' generally lower activity level and smaller body size:

• Neutered adult cat: RER × 1.2
• Intact adult cat: RER × 1.4
• Obesity-prone adult cat: RER × 1.0
• Kitten (growth): RER × 2.5

Most pet cats today are neutered, so most fall somewhere between the "obesity-prone" and "neutered adult" multipliers rather than the higher intact-cat figure — one reason a portion sized for a hypothetical "average cat" so often runs too high. As with dogs, the Merck Veterinary Manual is explicit that these are estimates, not exact prescriptions: an individual cat's real energy needs can run meaningfully higher or lower than the formula suggests, and the right way to fine-tune it is by tracking your cat's actual body weight and body condition over time, not by treating the calculated number as fixed.

Estimated Daily Calories by Weight (Healthy Adult Cat)

Using the RER formula above, here's what that looks like translated into approximate daily calorie ranges for a healthy adult cat at maintenance, spanning the obesity-prone-to-intact multiplier range (1.0–1.4× RER). These are starting-point estimates, not individualized recommendations — see the caveats above and below.

These figures are calculated from the published RER formula above for a resting-to-lightly-active adult cat. They do not account for growth, pregnancy/nursing, an unusually active or outdoor lifestyle, medical conditions, or individual metabolic variation — all of which can meaningfully change actual needs. A sedentary, neutered indoor cat will typically sit toward the lower end of its weight's range; a highly active or intact cat may sit toward the higher end.

From Calories to a Measured Portion: Why the Bag or Can Matters More Than Any Chart

A calorie target only becomes a usable portion once you know how many calories are actually in your specific food — and that varies a lot between products and between wet and dry formats. As an illustration, PetMD's own worked example uses Hill's Science Diet products at 181 kcal per 5.5-ounce can of wet food and 483 kcal per cup of dry food; on that basis, a cat with a 250-kcal/day target would get roughly two-thirds of that can, or about a quarter cup of that dry food, typically split across two or more meals. Swap in a different brand or formula and both of those numbers change, because calorie density isn't standardized across the category. The feeding guide printed on your cat's specific food, or the kcal-per-cup or kcal-per-can figure on the label combined with your cat's calorie target, is more accurate for your cat's actual food than any general chart — including this one. Our guide on how to read a pet food label covers where to find that information and what it does and doesn't tell you.

Why Meal Pattern Matters as Much as Amount for Cats

This is one of the clearest places cats and dogs actually diverge. A 2018 consensus statement on feline feeding from the American Association of Feline Practitioners (AAFP), summarized by the American Veterinary Medical Association, describes cats' natural feeding behavior as hunting and foraging for frequent small meals, eaten alone — a pattern very different from a dog's evolutionary history as a more opportunistic, meal-gulping scavenger. The consensus statement is direct that the two most common ways owners actually feed cats today — one or two large meals a day, or unlimited free-feeding — don't match that natural pattern, and it links free-feeding in particular to stress-related problems including obesity and feline cystitis (bladder inflammation). Its recommended alternative isn't a single fixed number of meals, but a feeding style built around the behavior: frequent small meals, puzzle feeders that make a cat work a little for food the way it would while hunting, and multiple feeding locations rather than one bowl a cat visits on cue.

None of this means every cat needs an elaborate foraging setup — a consistent, portion-controlled routine of two or three measured meals already improves on unmeasured free-feeding for most households. The point is that how a cat's calories are delivered matters for behavior and weight, not just the total number on a calculator.

Indoor Cats, Outdoor Cats, and the Obesity Question

Feline obesity is common enough that it's now closer to the norm than the exception in some populations. The Association for Pet Obesity Prevention's 2022 U.S. survey found 61% of cats were overweight or obese, and a separate UC Davis study of more than 9,000 cats found 41% met the specific clinical definition of obese (at least 20% above normal body weight) rather than merely overweight — two related but distinct figures worth keeping straight rather than treating as interchangeable. Indoor life is a major driver: a cat with no yard to patrol and nothing to hunt burns meaningfully fewer calories than the "intact adult" or "obesity-prone" distinction in the Merck multipliers above might suggest for a genuinely active cat, which is exactly why most sedentary, neutered, indoor cats — the majority of pet cats today — belong closer to the lower end of the calorie ranges in the table above, not the middle or top.

Outdoor or unusually active cats may reasonably need more than the formula's baseline suggests, but "my cat seems hungry" isn't a reliable substitute for tracking actual body weight and body condition — cats are also motivated to beg out of boredom or habit, independent of real caloric need. Our guide on telling if your dog or cat is overweight covers assessing body condition directly, a more reliable check than any calorie estimate alone.

Kittens, Seniors, and Other Situations That Change the Math

Kittens need substantially more calories relative to body weight than adult cats to fuel growth — the Merck Veterinary Manual's kitten multiplier of roughly 2.5× RER is more than double the neutered-adult figure — and should generally be fed a growth-formula food (see our guide on choosing the right cat food) with amounts following that product's own kitten feeding chart, adjusted regularly as they grow rather than left on a fixed portion.

Senior cats don't have a separate legally standardized AAFCO nutrient profile the way growth and adult-maintenance foods do — a "senior" label reflects a manufacturer's own formulation choices, not a fixed calorie or nutrient standard. Some older cats need fewer calories as activity drops; others, particularly with certain undiagnosed medical conditions such as hyperthyroidism or kidney disease, can lose weight despite eating normally or more. Unexplained weight loss or gain in an older cat is a reason to see a veterinarian rather than simply adjusting the bowl.

Cats that are already overweight or underweight shouldn't be fed to their current weight's calorie estimate — portion should be based on a target healthy weight your veterinarian helps you identify, not the number on the scale today, and any deliberate weight-loss plan for a cat should be done gradually and under veterinary guidance, since cats that lose weight too quickly are at risk of a serious liver condition called hepatic lipidosis.

Signs You May Be Over- or Under-Feeding

Rather than treating any calculated number as final, check your cat directly: you should generally be able to feel your cat's ribs under a slight layer of fat without pressing hard, and see a visible waist when looking down from above. Persistent begging isn't on its own reliable evidence of hunger, given how motivated cats can be to beg out of habit or boredom regardless of actual caloric need. Gradual weight gain or loss over several weeks, even on a "correctly calculated" portion, is a signal to reassess — with your veterinarian, if the trend continues or if your cat is losing weight unexpectedly.

A Word on Treats

Treats and extras count toward your cat's daily calorie total just as they do for dogs. The Pet Food Institute, a U.S. pet food industry association, advises keeping treats to no more than about 10% of a pet's daily calories, with the rest coming from a complete and balanced food — a useful check if a "correct" food portion still isn't maintaining a healthy weight and treats haven't been accounted for.

The Bottom Line

The RER/MER formula above gives you a defensible starting point for how many calories your cat needs, and your food's own label tells you how to turn that into an actual portion — but for cats, getting the calorie number right is only half the picture. How that food is delivered — as frequent small portions that engage some natural foraging behavior, rather than one or two large meals or unmeasured free access — matters for weight and wellbeing in a way that's more specific to feline biology than to dogs. If your cat's weight is trending in the wrong direction despite following label or formula guidance, or you're feeding a kitten, a pregnant/nursing cat, or a cat with a diagnosed medical condition, bring the specific numbers to your veterinarian rather than adjusting by guesswork.