Free Cat Weight Goal calculator with clear step-by-step results.
Feline weight loss has to be slow. Cats mobilise fat far less safely than dogs, and losing more than about 1-1.5% of body weight a week risks hepatic lipidosis, a serious liver condition. The plan therefore works backwards from a safe weekly rate: excess weight divided by the weekly loss gives the realistic timeline, and the feeding allowance is set at roughly 80% of resting energy requirement for the target weight — 70 × ideal weight^0.75 — rather than for the current weight.
Timeline
Weeks = (current weight − ideal weight) ÷ (current weight × weekly loss %)
Feeding allowance
Target kcal/day = 70 × ideal weight^0.75 × 0.8
Feline weight loss carries a real risk of hepatic lipidosis and must be supervised by a veterinarian. Do not restrict a cat's food based on a calculator, and never withhold food from a cat that has stopped eating — seek veterinary advice promptly.
Feeding to maintain the current weight maintains the current weight. Resting energy requirement is calculated from the target so intake falls to the level that sustains the cat you are aiming for.
Rapid caloric restriction in cats can trigger hepatic lipidosis, where fat overwhelms the liver. It is potentially fatal and is the main reason feline weight loss is managed slowly and under veterinary supervision.
From a body condition score assessed by your vet, not from breed averages. A score of 5 out of 9 is ideal, and each point above it corresponds to roughly 10% over ideal weight.