Enter your cat's weight, life stage or goal, and the calories printed on the food label. The calculator gives a daily calorie estimate and turns it into grams, and cups if you want them, for the dry or wet food you actually feed, including a split between the two.
The starting point is the resting energy requirement, or RER: the calories a cat's body needs in a day just to keep running while lying still, before any play or hunting. The formula is RER = 70 x body weight in kg raised to the power 0.75, from the 2021 AAHA Nutrition and Weight Management Guidelines. You don't need to work it out yourself; the calculator does it.
RER is then multiplied by a factor for your cat's life stage or goal. "1.2 x RER" means 1.2 times the resting figure. Where AAHA gives a range for a life stage, the calculator uses a single value from inside it. These are the values it uses:
A 4.5 kg neutered adult cat has an RER of about 216 kcal. At 1.2 x RER that is about 260 kcal a day. On a dry food with 3,800 kcal/kg, that works out to about 68 g a day.
Wet food carries far fewer calories per gram than dry food, so the same cat needs many more grams of it. If you feed both, the calculator can split the day between two foods.
The daily amount comes from dividing daily calories by the food's calorie density, meaning how many calories are in a kilogram or a cup of it. US labels carry a Calorie Content statement in kcal/kg and often kcal per cup or per can; EU and UK labels usually give kcal/kg or kcal/100g. The label guide shows where to find these numbers.
For weight loss, the AAHA guidelines base the calculation on the cat's ideal weight, not its current weight, and the Pet Nutrition Alliance calculator does the same. Enter the target weight your vet gave you. If you leave it blank, the calculator uses current weight, and the result will be higher than your vet's plan would give.
Take a 6 kg cat with a 5 kg target. Using the weight-loss factor on the target weight gives about 187 kcal a day. The same factor on its current 6 kg would give about 215.
Cats should not go on a sharp calorie cut at home. A cat that stops eating enough can develop hepatic lipidosis, a serious liver condition, so a weight-loss plan for a cat belongs with a veterinarian.
The result is a starting point for a healthy cat, not a diagnosis. Ask your vet before relying on it if your cat is pregnant or nursing, very overweight or underweight, diabetic, has kidney or heart disease, or is recovering from illness. Weigh your cat and check its body condition every two to four weeks, and adjust the amount gradually. Treats count toward the daily total.
It depends on your cat's weight and life stage. A 4.5 kg neutered adult cat needs about 260 kcal a day. Enter your cat's weight in the calculator for its daily estimate.
The calculator uses 2.5 x RER for kittens. A 2 kg kitten needs about 294 kcal a day. Re-weigh and recalculate as your kitten grows.
It depends on the food's calorie density, so there is no single gram figure for every food. A 4.5 kg neutered adult cat eating 260 kcal a day needs about 68 g of dry food with 3,800 kcal/kg. Use the calorie density on your own label in the calculator.
The calculator applies the weight-loss factor to the target weight. For a 6 kg cat with a 5 kg target, that gives about 187 kcal a day. A cat's weight-loss plan belongs with a veterinarian because a cat that stops eating enough can develop hepatic lipidosis, a serious liver condition.
Yes, the calculator can split daily calories between two foods. Wet food has far fewer calories per gram than dry food, so the gram amounts differ a lot.