๐Ÿˆ Cat Calorie & Portion Calculator

Work out how many calories your cat needs โ€” by weight, neuter status, life stage and body condition โ€” then turn that into grams of dry food and pouches of wet food, with a safe treat budget.

Nothing you enter leaves your device โ€” the whole calculation runs in your browser.

A โ€” Your cat
B โ€” The food you feed

The label tells you the energy content: dry food is usually 350โ€“420 kcal per 100 g and a typical 85 g pouch of wet food is 70โ€“100 kcal. Values in kcal per kilogram divide by 10 (3,800 kcal/kg = 380 kcal per 100 g).

Daily energy target
โ€” kcal
How this is worked out โ€” and the safety rules

The formula. Resting energy requirement (RER) = 70 ร— (body weight in kg)0.75. The daily target is RER multiplied by a life-stage and activity factor: neutered indoor adult ร—1.2 ยท entire active adult ร—1.4 ยท sedentary adult ร—1.0 ยท senior ร—1.2 ยท kitten under 4 months ร—3.0 ยท kitten 4โ€“6 months ร—2.5 ยท kitten 6โ€“12 months ร—2.0 ยท pregnant queen ร—2.0 ยท lactating queen up to ร—4.0 ยท weight loss ร—0.8. This is the RER/MER method used in the WSAVA Global Nutrition Toolkit and the AAHA/AAFP life-stage guidance.

Why the factor matters. Neutering lowers energy needs by roughly a fifth, so a cat fed the same amount after neutering gains weight. Indoor cats with unlimited food are the classic case: measure the portion rather than filling the bowl, and weigh the cat monthly.

Weight loss, done safely. Use the target weight, not the current weight, and a factor of 0.8. Aim for 1โ€“2% of body weight per week, no faster. Cats must never crash-diet: a cat that stops eating for more than 24โ€“48 hours can develop hepatic lipidosis (fatty liver), which is life-threatening. If your cat refuses the diet, or does not lose weight in a month, ask your vet for a prescription weight-management plan.

Treats. Keep treats to 10% or less of the daily calories, subtract them from the main food, and keep the total the same. A single treat can be a tenth of a small cat's day.

Water. A cat needs roughly 50 ml per kg per day โ€” more on dry food, less on all-wet. Wet food is about 78% water, which is part of why it helps cats that do not drink much. Water fountains and wider bowls encourage drinking.

Estimates, not prescriptions. Individual cats vary by up to about 30% from these figures. Weigh the cat every two to four weeks and adjust by 10% at a time. Kittens, pregnant or nursing queens, and cats with kidney, thyroid, heart or gut disease need a vet's plan, not a calculator.

Body condition. The 9-point scale used here is the standard hands-on test: ideal cats (4โ€“5) have ribs you can feel under a thin fat layer, a visible waist from above and a small tummy tuck from the side. Estimates only โ€” not veterinary advice. Factors checked 4 October 2026 against the WSAVA Global Nutrition Toolkit, the AAHA/AAFP 2021 Feline Life Stage Guidelines and the AAHA Weight Management Guidelines.