Cat Calorie Needs Calculator
This calculator estimates your cat's daily calorie needs using the National Research Council (NRC) formula. Resting Energy Requirement (RER) = 70 x (body weight in kg) raised to the power of 0.75. The RER is multiplied by a life-stage factor to produce the daily Maintenance Energy Requirement (MER). Enter your cat's current weight (or ideal weight for a weight-loss plan), choose the appropriate life stage, and the calculator returns daily kcal needed. Divide that figure by the kcal-per-serving shown on your cat food packaging to find the right portion size.
Cat calorie formula (NRC)
RER (kcal/day) = 70 x (body weight in kg)^0.75
MER (kcal/day) = RER x life-stage factor
Published by the National Research Council in "Nutrient Requirements of Dogs and Cats" (National Academies Press, 2006). The metabolic body weight exponent (0.75) accounts for the relationship between body size and resting metabolic rate in cats.
Life-stage multipliers for cats
- Neutered adult (indoor): 1.2 x RER
- Intact adult: 1.4 x RER
- Weight loss: 0.8 x RER (use ideal/target weight)
- Weight gain: 1.8 x RER
- Kitten under 4 months: 2.5 x RER
- Kitten 4 months to adult size: 1.8 x RER
- Late gestation: 1.6-2.0 x RER
- Peak lactation: up to 4.0-6.0 x RER
Cat calorie needs calculator: frequently asked questions
What formula is used for cat calorie requirements?
The National Research Council (NRC) Resting Energy Requirement formula for cats is: RER = 70 x (body weight in kg)^0.75. This is multiplied by a life-stage factor to get the daily Maintenance Energy Requirement (MER).
What life-stage multipliers apply to cats?
NRC-based multipliers for cats include: neutered adult 1.2, intact adult 1.4, weight loss 0.8 x RER, weight gain 1.8 x RER, kitten under 4 months 2.5, kitten 4 months to adult 1.8, late gestation 1.6-2.0, peak lactation up to 2.0-6.0.
My cat is overweight. How many calories should I feed?
For weight loss, the NRC recommends feeding at approximately 0.8 x RER, calculated from the cat's ideal target weight rather than its current weight. Always confirm a weight-loss plan with your veterinarian.
How do wet and dry cat foods differ in calorie density?
Wet foods typically contain 70-80% moisture and run 25-50 kcal per 100 g. Dry kibble runs 300-400 kcal per 100 g. Always check the package for exact kcal per serving, then divide your cat's daily requirement to get the serving size.
Are these calorie figures accurate for every cat?
They are population-average estimates from the NRC. Individual cats may need 10-30% more or less depending on genetics, breed, health status, and home temperature. Monitor body condition score monthly and adjust food accordingly.
Official sources
- National Research Council: Nutrient Requirements of Dogs and Cats (2006).
- American Animal Hospital Association (AAHA): 2021 AAHA Nutrition and Weight Management Guidelines.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.