Dr. Priya Anand, DVM, ABVP (Feline) · Last reviewed July 6, 2026

Cat Diet & Weight-Management Calculator

How many calories does your cat need — and how much food is that, really? Enter your cat's weight, life stage, and goal to get a daily calorie target and the exact portion in cups or cans. Trying to trim an overweight cat down safely? Switch on weight-loss mode and enter a target weight. No signup, no ads.

Cat diet and weight-management calculator: enter your cat's weight, life stage, and goal to get their daily calories and how much food to feed.

lb
Food type

Find kcal/cup or kcal/can on your food's label or the brand's site — defaults are typical, but your food's real number makes the portion exact.

Enter your cat's weight above and we'll show their daily calories and exactly how much food to serve.

Quick feeding chart (kcal/day)

Tap a row to load that weight
Weight Maintain Slim down to
6 lb 178 119
8 lb 221 147
10 lb 261 174
12 lb 299 200
14 lb 336 224
16 lb 371 248
18 lb 406 270
20 lb 439 293

"Maintain" = a spayed/neutered adult (1.2 × RER). "Slim down to" = feeding for that weight as the ideal target (0.8 × RER). Based on the veterinary RER/MER equations — the calculator above tailors these to your cat's exact profile and food.

A starting point, not a prescription. These figures use standard veterinary energy equations and are a sensible place to begin — real needs vary with metabolism, activity, and health. Weigh your cat monthly and adjust. Never crash-diet a cat: rapid weight loss can trigger a dangerous liver condition (hepatic lipidosis), so run any weight-loss plan past your veterinarian and aim for slow, steady loss. Reviewed by Dr. Priya Anand, DVM, ABVP (Feline).

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How to use this cat diet calculator

  1. Enter your cat's current weight. Use the + / − steppers or type it in, and switch between pounds and kilograms with the toggle. Not sure? A vet visit will have it on the record — or use the average cat weight ranges as a rough guide.
  2. Pick their life stage and status. Kitten, adult (spayed/neutered, intact, or indoor/low-activity), or senior. This sets the metabolic factor the vet formula uses.
  3. Choose a goal. Leave it on Maintain for a healthy-weight cat, or switch to Lose or Gain and enter a target (ideal) weight — the calculator then feeds for that goal weight, the way a vet weight-loss plan does.
  4. Set the food. Dry, wet, or both. Enter the food's calories per cup or per can (it's on the label), pick how many meals a day, and for mixed feeding drag the slider to split calories between wet and dry.
  5. Read the result instantly. The daily calorie target and the exact portion recalculate the moment you change anything — no "calculate" button. Then copy it, share a link that reopens the same setup, or download a branded feeding-plan PDF for the fridge or a pet-sitter.

Why this cat diet calculator is different

Most "cat calorie calculators" stop at a number of calories — which is useless at the food bowl, because nobody serves calories, they serve cups and cans. This tool goes the whole way.

  • It gives you calories and portions. Enter your food's kcal per cup or per can and you get the actual amount to scoop — for dry food, wet food, or a wet-and-dry mix with a split slider.
  • It does weight management properly. For weight loss it feeds for the target weight (the clinically correct method), not just a blanket cut of the current intake — and it warns you to go slow, because cats that drop weight too fast risk a serious liver condition.
  • It adapts to the whole cat. Kitten, intact, neutered, indoor couch potato, or senior — each uses the right veterinary energy factor instead of one-size-fits-all math.
  • It's portable and shareable. Real-time recompute, a share link that remembers every setting, and a printable feeding-plan PDF a pet-sitter can follow exactly.
  • It shows its work. The RER/MER equations are printed on this page, and an automated fixture test runs on every build so the math can't quietly drift. Reviewed by a board-certified feline veterinarian.

How cat calorie needs are calculated

Vets don't guess feeding amounts — they use two equations. This calculator runs the same ones:

  • Resting Energy Requirement (RER) is the calories a cat burns at rest: RER = 70 × (body-weight-in-kg)0.75. A 4 kg cat has an RER of about 198 kcal.
  • Maintenance Energy Requirement (MER) multiplies RER by a life-stage factor: ×1.2 for a spayed/neutered adult, ×1.4 intact, ×1.0 for a low-activity indoor cat, ×1.1 senior, and ×2.0–2.5 for growing kittens. So that same 4 kg neutered adult needs roughly 198 × 1.2 ≈ 238 kcal a day.
  • For weight loss, the calculator switches the math to the ideal weight and feeds 0.8 × RER of that target — a controlled deficit that trims fat while protecting muscle. Weight gain uses 1.4 × RER of the goal weight.

To turn calories into a portion, it divides the daily target by your food's energy density — the kcal per cup (dry) or kcal per can (wet) printed on the label — then splits it across the number of meals you feed. If you're unsure how wet and dry compare, our guide to how much wet food to feed a cat walks through the trade-offs.

Three worked examples

The healthy 10-pound adult

A 10 lb (4.5 kg) spayed indoor cat at a good weight needs about 260 kcal a day to maintain. On a dry food at 400 kcal/cup that's roughly ⅔ cup a day, or about ⅓ cup at each of two meals. Feed that consistently, weigh her monthly, and adjust if the number on the scale drifts.

Slimming down a 15-pounder

A 15 lb cat whose vet says 11 lb is ideal shouldn't just eat "less." Set the goal to Lose and enter 11 lb as the target: the calculator feeds for that goal weight (about 235 kcal/day), a deliberate, muscle-sparing deficit. The key is patience — aim for a cat losing weight slowly over months, and always run a weight-loss plan past your vet, because crash-dieting a cat can trigger dangerous hepatic lipidosis.

The growing kitten

A 3.3 lb (1.5 kg) four-month-old kitten is in overdrive: at 2.5 × RER that's about 237 kcal a day of calorie-dense kitten food, split into several small meals. Notice the goal toggle switches off — kittens are never put on a diet; they're fed for growth until their first birthday.

Frequently asked questions

How many calories does my cat need per day?

Most healthy, neutered adult indoor cats need somewhere between 180 and 280 calories a day, depending on their weight. The exact number comes from the veterinary formula this calculator uses: 70 × (weight in kg)0.75, times a factor of about 1.2 for a typical adult. Enter your cat's weight above for their specific target.

How much should I feed my cat each day?

Feed to the calorie target, not to a generic "cup a day." Once you know the daily calories, divide by your food's kcal per cup (dry) or kcal per can (wet) — both are on the label. As a rough anchor, a 10 lb cat on a 400 kcal/cup dry food eats about ⅔ cup daily, but the right amount depends entirely on your specific food's density, which is why this tool asks for it.

How much should I feed my cat to lose weight?

Feed for the ideal weight, not the current one. The clinically sound approach is roughly 80% of the resting calories for the target weight — which this calculator does automatically when you switch to weight-loss mode and enter a goal weight. Just as important: go slowly. Rapid weight loss in cats can cause a life-threatening liver condition (hepatic lipidosis), so any weight-loss plan should be supervised by your veterinarian.

Is dry or wet food better for portioning?

Both work — the calorie math is identical; only the density differs. Wet food is far lower in calories per gram and higher in moisture, which helps with hydration and satiety, while dry food is calorie-dense and convenient. Many owners feed both. This calculator handles all three (dry, wet, or a custom split), and our best wet cat food and best cat food guides cover picks for each.

Can I embed this cat diet calculator on my website?

Yes — copy the embed snippet at the bottom of this page. The embedded version is a clean, ad-free widget made for rescues, foster networks, veterinary educators, and cat blogs. Required attribution is built in; there's no fee, signup, or tracking.

Once the calculator lands on a number, it suggests a few things that fit the goal — a weight-management food and a gram scale for cats slimming down, calorie-dense wet food for cats that need to gain, and kitten formula plus a climbing tree for the little ones. For the full shortlist in each category, see Dr. Anand's guides to the best cat food and the best wet cat food.

Methodology & sources

Daily calories use the veterinary energy equations: RER = 70 × (body-weight-kg)0.75 and MER = RER × life-stage factor (neutered adult 1.2, intact 1.4, indoor/low-activity 1.0, senior 1.1, kitten 2.0–2.5). Weight loss uses 0.8 × RER of the target weight and weight gain 1.4 × RER of the target weight — the target-weight method used in veterinary weight-management programs. Portions divide daily calories by the food's stated kcal per cup or per can. The figures are validated by an automated fixture test — calories, portions, and a reference table cross-checked against a published feeding chart — that runs on every site build.

Reviewed annually for citation currency. About Dr. Anand · Last reviewed July 6, 2026.

Cite this page

Free to cite or link in coursework, handouts, and articles — no permission needed.

Anand, P. (2026, July 6). Cat Diet & Weight-Management Calculator. House of Mittens. https://houseofmittens.com/cat-diet-calculator/

Embed this cat diet calculator

Free for rescues, foster networks, veterinary educators, and cat blogs. Required attribution is included in the snippet — no fee, no account, no tracking. 

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  Cat diet calculator by
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  &middot; Reviewed by Dr. Priya Anand, DVM, ABVP (Feline)
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