Cat Daily Calorie Calculator
A cat's daily calorie target starts from its resting energy requirement, the energy burned at rest, then scales up with a factor for activity, neuter status, and life stage. This calculator uses the standard veterinary resting energy formula (70 times body weight in kilograms to the power 0.75) and multiplies it by the life-stage factor you choose. Enter weight in pounds or kilograms and pick a factor to get an estimated kilocalories-per-day figure, then divide by your food's energy density to convert it into a feeding amount. Treat the result as an educational starting point and confirm with your veterinarian.
1.2 inactive, 1.4 neutered adult, 1.6 intact adult, 2.0 gain, 2.5 lactation/kitten.
Cat calorie requirement formula
Weight (kg) = pounds / 2.2046226
RER = 70 * (weight in kg ^ 0.75)
DER = RER * life-stage factor
Per meal = DER / 2
RER is the resting energy requirement and DER is the daily energy requirement after applying the activity factor. Both are expressed in kilocalories (the "calories" on pet food labels). Divide DER by the food's kcal per cup or can to get a portion size.
Feeding context
- The exponential RER formula (70 times kg to the 0.75) is the standard small-animal resting energy estimate used in clinical veterinary nutrition.
- Life-stage factors are guidance values, not exact constants; body condition score is a better day-to-day guide than any single multiplier.
- Neutering lowers energy needs, which is why a neutered adult factor (about 1.4) is lower than an intact one (about 1.6).
- Growing kittens and lactating queens have the highest needs, often 2 to 3 times resting energy.
- Always cross-check against the feeding guide on your specific food and adjust to maintain a healthy weight.
Cat calories: frequently asked questions
How is a cat's daily calorie requirement calculated?
Start with resting energy requirement (RER), the calories a cat burns at rest. The standard veterinary formula is RER = 70 times body weight in kilograms raised to the power 0.75. Daily energy requirement (DER) is then RER multiplied by a life-stage factor that reflects activity, neuter status, and physiological state.
What life-stage factor should I use for my cat?
Common multipliers cited in veterinary nutrition references are roughly 1.2 for an inactive or weight-loss adult, 1.4 for a neutered adult, 1.6 for an intact adult, 2.0 for weight gain or pregnancy, and 2.5 for lactation or growing kittens. These are starting points; adjust based on body condition and your veterinarian's advice.
Why is the exponent 0.75 used?
Metabolic rate does not scale linearly with body mass. Across mammals, resting energy expenditure scales close to body weight to the power 0.75, a relationship known as metabolic body size or Kleiber's law. Using this exponent gives a more accurate estimate than a simple per-kilogram multiplier, especially across the range of cat sizes.
Is this calculator a substitute for veterinary advice?
No. This is an educational estimate. A cat's true energy needs depend on age, health conditions, body condition score, environment, and the energy density of the specific food. Always confirm feeding amounts with your veterinarian and follow the feeding guide on the food label.
How do I convert calories into a feeding amount?
Divide the daily calorie target by the energy density of the food, listed on the label as kilocalories per cup, per can, or per kilogram. For example, a 250 kcal/day target with a food providing 500 kcal per cup means half a cup per day, split across the cat's normal number of meals.
Official sources
- U.S. FDA Center for Veterinary Medicine: Animal & Veterinary.
- National Academies Press: Nutrient Requirements of Dogs and Cats (NRC).
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.