Pet Resting Energy (RER)

About this calculator

Resting Energy Requirement (RER) is the number of calories a dog or cat burns at complete rest just to keep basic body functions running, calculated from the widely used veterinary formula RER = 70 × (body weight in kg)^0.75. It is the foundation figure that every other feeding calculation in veterinary nutrition builds on top of.

Veterinarians and veterinary nutritionists multiply RER by a life-stage or activity factor — roughly 1.2 to 1.4 for an average indoor adult, higher for growing puppies and kittens, lactating animals or working dogs, and lower for weight loss or a sedentary senior pet — to arrive at the actual Maintenance Energy Requirement (MER) used to set a daily feeding amount. Pet food labels and prescription weight-management diets are formulated around exactly this RER-then-multiplier logic, which is why vets ask for a pet’s weight before recommending how much of a given food to feed per day.

Enter your pet’s weight and this calculator computes RER in kilocalories per day using the standard exponential formula, giving you the baseline figure to apply your own activity multiplier to.