How much should you feed your cat each day? Too much food is the fastest route to an overweight cat — and overweight cats face a much higher risk of diabetes, joint pain and liver disease. Too little food leaves a cat hungry, underweight and short of the protein cats need as strict carnivores. Our free Cat Feeding Calculator works out your cat’s daily calorie needs using the same veterinary method vets use: it first calculates the Resting Energy Requirement (RER) from body weight, then multiplies it by a life-stage factor for kittens, neutered indoor adults, active cats, seniors and cats on a weight-loss plan. You get the answer in calories per day, plus a practical grams-per-day amount for a typical dry food, so you can weigh the bowl with confidence instead of guessing.
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Why Use a Cat Feeding Calculator?
The feeding guide printed on a food bag is a rough average for a “typical” cat — but there is no typical cat. A neutered indoor cat that sleeps sixteen hours a day needs far fewer calories than an intact outdoor cat that patrols a garden, and a growing kitten needs roughly twice the energy per kilo of a relaxed adult. Feeding by the bag’s average is exactly how so many indoor cats slowly gain weight: studies and vet surveys regularly find that a large share of pet cats are overweight, and most owners honestly did not realise it was happening, because a few extra grams of kibble a day add up quietly over months.
- A personal calorie target: based on your cat’s actual weight and life stage, not a bag average.
- Portion control in grams: weighing food takes ten seconds and removes all guesswork.
- Safer weight loss: the weight-loss setting targets the cat’s resting needs, the level vets commonly start from — never crash-diet a cat.
- Better kitten growth: growing kittens need far more energy per kilo than adults; the kitten setting reflects that.
Cat Feeding Explained — RER and DER
Veterinary nutrition works in two steps. First comes the Resting Energy Requirement (RER) — the calories a cat burns just staying alive at rest: RER = 70 × (body weight in kg)0.75. For a 4 kg cat that is about 198 kcal a day before any activity is added. The second step multiplies RER by a factor for the cat’s life stage and lifestyle, giving the Daily Energy Requirement (DER) — the number you actually feed. Growing, reproducing and active cats get higher factors; neutered indoor cats and cats that must lose weight get lower ones.
| Life Stage / Activity | Factor (× RER) | Why |
|---|---|---|
| Kitten (growing) | 2.0 | Growth is expensive: kittens build bone, muscle and brain tissue fast. |
| Adult — neutered, indoor | 1.2 | Neutering and indoor life both lower energy needs. |
| Adult — intact | 1.4 | Unneutered cats are generally more active and burn more. |
| Active / outdoor | 1.6 | Roaming, hunting behaviour and cold weather raise the burn rate. |
| Senior | 1.1 | Older, less active cats need slightly less — but keep protein high. |
| Weight loss | 1.0 | Feeding at resting level creates a gentle, safe calorie deficit. |
Worked example: a 4 kg neutered indoor adult has an RER of about 198 kcal. Multiplied by 1.2, that gives about 238 kcal per day — roughly 63 g of a typical dry food at 380 kcal per 100 g. Notice how much smaller that is than the generous bowl many cats are served; that gap is where weight gain hides.
Dry Food, Wet Food and the Label
The calorie target stays the same whatever you feed — what changes is the weight of food in the bowl. Dry foods are energy-dense, commonly around 350–400 kcal per 100 g. Wet foods are mostly water, often only 70–100 kcal per 100 g, so a cat eating wet food will get a much heavier bowl for the same calories. That is why this calculator leads with calories and gives grams for one typical dry food only. Find the “kcal per 100 g” (or per kg) figure on your own brand’s label, divide your cat’s daily calorie target by it, and you have your exact grams. If your cat eats a mix of wet and dry, split the calorie target between them — for example, half the calories from a morning wet pouch and half from weighed evening kibble. Treats count too: keep them under about 10% of the daily total and subtract them from the main meals.
How to Use This Calculator
- Weigh your cat. The easiest way: weigh yourself holding the cat, then weigh yourself alone and subtract. Use your cat’s current weight, or the target weight your vet set if your cat is on a weight-loss plan.
- Choose the life stage that matches your cat best — when in doubt between two, the neutered indoor setting fits most pet cats.
- Click “Calculate Daily Food” to see the daily calories and the dry-food grams. Weigh portions with a kitchen scale and split them into at least two meals a day.
- Recheck every month. Weigh your cat monthly and adjust: if the weight is drifting the wrong way, change the portion by about 10% and check again in a few weeks.
Feeding Kittens, Seniors and Multi-Cat Homes
Kittens should have food available in several small meals — four a day at eight weeks old, dropping to two or three by six months. Use the calculator as a floor rather than a ceiling while they are growing, and switch to the adult setting once your vet says growth is complete, usually around 10–12 months. Senior cats need slightly fewer calories but more digestible protein, not less, to protect their muscle; sudden appetite or weight loss in a senior is a vet visit, not a bigger bowl. In multi-cat homes, feed separately or use microchip feeders — the bold cat eating two dinners is the most common hidden cause of one fat cat and one thin cat in the same house.
Educational & Veterinary Disclaimer
This calculator provides educational estimates based on the standard RER formula and commonly used life-stage factors. Individual cats vary with breed, health, metabolism and exact activity, so treat the result as a starting point and adjust it against your cat’s real weight trend. It is not veterinary advice. Cats should never lose weight quickly — rapid restriction can trigger a dangerous liver condition (hepatic lipidosis), especially in overweight cats — so always follow a vet-guided plan for weight loss, and see a vet promptly for sudden appetite or weight changes.
High-Authority References & Sources
- American Animal Hospital Association (AAHA) — nutrition and weight management guidelines for cats.
- American Veterinary Medical Association (AVMA) — pet nutrition and healthy-weight resources for owners.
- Merck Veterinary Manual — energy requirement (RER/DER) calculations in veterinary nutrition.
- Cornell Feline Health Center — feeding and obesity information for cats.
- International Cat Care — practical feeding and weight-care guides for cat owners.
Related Pet Calculators
- Cat Weight Calculator
- Cat Age Calculator
- Cat Pregnancy Calculator
- Dog Feeding Calculator
- All Pets Calculators
Frequently Asked Questions (FAQ)
How many calories does a cat need per day?
Most neutered indoor adult cats need roughly 200–260 kcal a day. The exact figure depends on weight and lifestyle: a 4 kg indoor cat needs about 238 kcal, while an active outdoor cat of the same weight needs over 300 kcal.
How much dry food should I feed a 4 kg cat?
About 63 g per day of a typical dry food (380 kcal per 100 g) for a neutered indoor 4 kg cat. Always check your own brand’s calorie density on the label, because brands differ.
How much should I feed my kitten?
Kittens need about twice the calories per kilo of an adult while they grow. Use the Kitten setting above, serve it in several small meals a day, and use a kitten-formula food until about 10–12 months of age.
How do I help my cat lose weight safely?
Feed at the Weight Loss setting (resting energy level), weigh every portion, cut treats to under 10% of calories, and aim for slow loss of about 0.5–1% of body weight per week with vet check-ins. Never starve a cat or cut food drastically — rapid weight loss can cause a dangerous liver condition.
Is wet food or dry food better for portion control?
Both can work. Wet food is less calorie-dense, so cats feel fuller on more volume, which helps some overweight cats. Dry food is easier to weigh precisely. What matters most is matching total calories to your cat’s target and checking the label of the food you actually use.