Cat Food Calculator — how much to feed your cat 🐟

What the calculator is actually doing

The starting point is the resting energy requirement — the calories a cat burns just existing: breathing, circulating blood, maintaining body temperature, running the world's most judgemental brain. It doesn't scale in a straight line with weight; a 15 lb cat does not need half again the calories of a 10 lb cat. The veterinary formula raises body weight to the power of 0.75 to follow that curve, which is the exponent you see in the math note above.

Resting energy then gets multiplied by a life-stage factor: a growing kitten builds a body as well as running one and needs up to three times its resting requirement per pound; a neutered adult flopped on a windowsill needs barely more than resting; a nursing queen with five kittens is running the highest energy demand a cat ever experiences — often more than double maintenance. Getting the life stage right matters more than any other input.

The output is calories per day. Converting calories into actual food needs one number that only your food's own packaging has — which brings us to the label.

The label number everything depends on

Cat foods vary enormously in energy density. Dry foods run roughly 300–500 kcal per cup; wet foods roughly 60–110 kcal per 3 oz can, mostly because wet food is about 75–80% water. Feed “half a cup twice a day” of two different dry foods and you can be 40% apart in calories without knowing it.

Find the kcal/kg or kcal/cup (or per can) figure — labeled “ME” (metabolisable energy), usually in small print near the feeding table. Divide the day's calorie target by it and you have the portion. Two upgrades make this far more accurate: weigh dry food in grams on a kitchen scale rather than scooping (cup measures of kibble run wildly inconsistent, and for a creature this small a daily error of 20 kibbles is a diet trend), and re-check the label whenever you buy a different variety — even flavors within one brand differ.

Wet, dry, or both?

Both can feed a cat well, and the honest answer is that the best food is one your cat reliably eats, you can afford, and that keeps their body condition ideal. The genuine differences:

• Water. Cats descend from desert animals with a famously weak thirst drive — many chronically under-drink on dry-only diets. Wet food carries its own water, which is why vets often steer cats with urinary issues towards it.
• Calorie density. Dry food packs more calories into less bulk — convenient, but easier to overfeed, especially free-choice. Wet food's bulk-per-calorie helps dieting cats feel fed.
• Practicalities. Dry suits puzzle feeders, timed feeders and grazers; wet spoils within the hour in a warm room. Mixed feeding — wet meals plus a measured dry ration — is a perfectly good compromise many households settle on.

Whatever the format, pick a food whose label states it meets AAFCO (or FEDIAF) nutritional adequacy for your cat's life stage — that line is the difference between a complete diet and a supplemental treat food.

Meals, grazing, and the food-bowl politics of multi-cat homes

Free-choice feeding — a bowl that is never empty — is how a large fraction of indoor cats end up overweight; most cats will graze past their needs when calories cost nothing. Measured meals win: two to four a day for adults suits feline digestion and lets you notice immediately when a cat goes off food, which is one of the earliest illness signals cats give.

Multi-cat households add the real complication: cats steal. A dieting cat and a thin senior sharing a kitchen need separate feeding stations — different rooms with the door pushed to, a microchip feeder that opens only for the right cat, or simply supervised meals picked up after twenty minutes. Feeding the household average is how one cat gets fat while another fades.

Treats count inside the day's total, and the guideline is the same as for dogs: no more than 10% of daily calories. For a 250-calorie cat that is 25 calories — four or five commercial treats, not a handful. Take treats out of the measured ration rather than adding them on top, and remember that a saucer of milk is a treat too (and one many adult cats can't digest — most are lactose intolerant).

Feeding a cat down to a healthy weight — the one rule that is not optional

Here cats differ from every other pet in the house, and the difference is dangerous: a fat cat that stops eating can develop hepatic lipidosis — fatty liver — within days. When an overweight cat's calories crash, fat floods the liver faster than it can be processed, and the resulting liver failure is life-threatening. Crash-dieting a cat, or a cat going on hunger strike against a new diet food, is a genuine emergency in the making.

So feline weight loss is deliberately gentle:

• Target 0.5–2% of body weight per week — for a 14 lb cat, one to four ounces. Months, not weeks, are the unit of a cat diet.
• Use the weight-loss mode above with the target weight, not the current one, and confirm the target with your vet first.
• Transition food changes over one to two weeks, and if the cat refuses the new food, do not wait it out the way you might with a dog — a cat that eats nothing for 48 hours needs a vet.
• Make the calories harder to get: puzzle feeders, food balls, portions split across the house, meals upstairs — hunting effort is exercise a cat will actually do.
• Weigh fortnightly. Baby scale or the weigh-yourself-holding-the-cat trick; our Is My Cat Overweight? tool tracks the body-condition side.

Kittens, pregnancy and nursing: when the multiplier goes up

Kittens under four months are growth machines — the 3.0 multiplier above is real, and it is why kittens eat little and often (three to four meals, or measured free access at this age only) and need a food formulated for growth, not adult maintenance. From four months to a year the multiplier steps down as the curve flattens; our Kitten Weight Predictor shows where on the curve a kitten sits.

A pregnant queen's needs rise steadily to roughly 1.5–2× maintenance by the end of her nine weeks — the standard advice is to move her onto kitten food from mid-pregnancy and let her eat generously. Nursing is the extreme case: a queen with a large litter can need two to three times maintenance and is usually fed effectively free-choice on kitten food until weaning. Timeline and care details live in our Cat Pregnancy Calculator.

Seniors, finally, break the stereotype: unlike dogs, many cats' energy needs rise past about eleven years as digestion grows less efficient, and unplanned weight loss in an older cat eating normally is a classic early sign of hyperthyroidism, kidney disease or diabetes — a vet visit, not a bigger scoop.

The signs you got the portion right

The calculator's number is a starting point; the cat is the feedback loop. Run the hands-on check monthly: ribs easy to feel under a light fat cover, a visible waist from above, a modest belly. (The swinging pouch low on the belly is the primordial pouch, standard feline equipment even on lean cats — judge the ribs, not the pouch.) Holding ideal condition on the current portion means the number is right, whatever any chart says. Drifting up or down a quarter-pound per month means nudging calories about 10% and re-checking in two weeks — small rudder corrections, not lurches.

Frequently asked questions

How much should I feed my cat per day?

Work from calories, not cups: the veterinary formula is RER = 70 x (weight in kg)^0.75, multiplied by a life-stage factor (about 1.2 for a typical neutered adult, up to 3.0 for young kittens). A typical 10 lb neutered adult lands around 250-280 kcal/day. Convert to food using the kcal figure on your own bag or can, since energy density varies hugely between foods.

How many cups of dry food does a cat need?

It depends entirely on the food's energy density - dry foods run roughly 300-500 kcal per cup, so the same cat might need 0.5 cups of one food and 0.9 of another. Divide the daily calorie target by your bag's kcal-per-cup figure, and better still weigh the portion in grams; scoop technique alone can vary a 'cup' by a fifth.

Is wet or dry food better for cats?

Both can be complete diets; the real differences are water and calorie density. Wet food carries the water that low-thirst-drive cats often skip, which is why vets favor it for urinary issues; dry is cheaper per calorie, suits puzzle and timed feeders, but makes overfeeding easier. Mixed feeding is a legitimate middle path. Whatever you choose, check the label meets AAFCO adequacy for the life stage.

Why is my cat always begging for food?

Usually learned economics, not hunger: begging that ever pays is reinforced. Rule out a genuinely inadequate portion (check against calories, and body condition), rapid-onset ravenousness with weight loss (hyperthyroidism and diabetes both cause it - vet visit), then make meals more frequent but measured, feed some of the ration through puzzle feeders, and let an automatic timed feeder take the blame for schedules.

Can I put my cat on a diet by just feeding much less?

No - severe restriction is dangerous for cats specifically. An overweight cat whose intake crashes can develop hepatic lipidosis (fatty liver), a life-threatening condition, within days. Feline weight loss should run at 0.5-2% of body weight per week using a measured, gradual reduction - and a cat that refuses food for more than a day or two needs a vet, not patience.

How often should I feed my cat?

Adults: two to four measured meals a day beats free-choice, which quietly overfeeds most indoor cats and hides the appetite loss that is often a cat's first illness signal. Kittens under four months need three to four small meals. In multi-cat homes, feed separately - different rooms or microchip feeders - so portions actually reach the cat they were calculated for.