Cat Calorie Calculator — Daily Food Energy for Cats
Find out exactly how many kilocalories your cat should eat each day. Uses the veterinary Resting Energy Requirement (RER) formula — 70 × body weight (kg)^0.75 — multiplied by a life-stage factor recommended by the NRC and WSAVA.
Weight unit
kg
Life stage / status
Maintenance Energy Requirement (MER) — total daily food energy needed
- 1
Resting energy (RER)
70 × 4^0.75 = 198Allometric formula — BW^0.75 (metabolic body weight) scales RER across body sizes (Kleiber's law) - 2
Life-stage multiplier
× 1.2Neutered adult - 3
Daily calorie needs (MER)
198 × 1.2 = 238
How does this calculator work?
Cat daily calories = 70 × (weight in kg)^0.75 × life-stage multiplier. A 4 kg neutered adult needs roughly 70 × 4^0.75 × 1.2 ≈ 200 kcal/day. Kittens need 2.5–3× that multiplier; weight-loss cats need 0.8×. Adjust based on 4–6-week weight checks.
Formula
How this is calculated
Feline calorie needs are calculated in two steps. First, the Resting Energy Requirement (RER) — the energy a cat needs just to maintain basic body functions at rest — is estimated by the allometric formula RER = 70 × BW_kg^0.75, where BW_kg is body weight in kilograms. The 0.75 exponent (the metabolic body weight) accounts for the non-linear scaling of metabolism with body size, as established by Kleiber's law.
Second, the Maintenance Energy Requirement (MER) — the actual daily food intake target — is obtained by multiplying RER by a life-stage factor. These factors, published by the National Research Council (NRC 2006) and the World Small Animal Veterinary Association (WSAVA 2011), reflect how activity, reproductive status, and growth change energy needs: kittens need up to three times RER for rapid growth, while inactive or obese-prone adults need only 1.0 times RER. Weight-loss protocols commonly target 0.8 × RER.
The result is a starting guideline, not a prescription. Cats vary in individual metabolic rate, coat density, ambient temperature, and food digestibility. Monitor your cat's weight over 4–6 weeks and adjust portions if weight is not tracking toward the ideal. Consult your vet before making significant dietary changes.
Frequently asked questions
RER stands for Resting Energy Requirement — the calories a cat needs just to maintain bodily functions at rest (breathing, circulation, cell repair). It is calculated as 70 × (body weight in kg)^0.75. Actual daily intake (MER) is RER multiplied by a factor that accounts for activity and life stage.
Divide the daily calorie target (MER) by the caloric density of the food, listed on the packaging as kcal/100 g or kcal/cup. For example, if your cat needs 250 kcal/day and the food has 340 kcal/100 g, feed approximately 74 g per day. Wet food is typically 70–100 kcal/100 g; dry food 300–400 kcal/100 g.
Manufacturer feeding guides are broad averages and frequently overestimate — leading to gradual weight gain. Using the RER formula based on your cat's actual weight (or, better, their ideal weight) and adjusting to results is more accurate. Always check with your vet for cats with medical conditions.
TG we-Calculate Editorial Team. (2026). Cat Calorie Calculator — Daily Food Energy for Cats [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cat-calorie-calculator
TG we-Calculate Editorial Team. "Cat Calorie Calculator — Daily Food Energy for Cats." TG we-Calculate. 2026. https://we-calculate.com/calculator/cat-calorie-calculator.
TG we-Calculate Editorial Team, "Cat Calorie Calculator — Daily Food Energy for Cats," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cat-calorie-calculator
@misc{wecalculate_cat_calorie_calculator, title = {Cat Calorie Calculator — Daily Food Energy for Cats}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cat-calorie-calculator}}, year = {2026}, note = {TG we-Calculate} }
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