How a daily cat food portion is worked out
A cat portion starts from the body weight, turns into a daily calorie figure, and is then divided by the energy of the food to give a weight. Enter the weight, a cat energy factor, the food type, the kcal per ounce from the label and the number of meals, and the tool returns a daily amount and a per-meal amount.
The resting energy requirement uses RER = 70 x kg^0.75, the formula AAHA and WSAVA both rely on. Because sources differ slightly on the factors, the widely used cat values are shown as numbers in the dropdown with a custom field beside them. Pounds are converted to kilograms internally and both are shown. Content is current as of October 2026.
Illness, pregnancy and nursing are not covered, and splitting a day between wet and dry food is handled by a separate tool. This tool is for reference only and does not replace veterinary care. Contact your veterinarian right away if you notice symptoms or suspect a problem.
Frequently asked questions
At the same body weight a cat is credited with less maintenance energy, so the usual values run lower: 1.2 for a neutered adult cat and 1.4 for an intact one, with 0.8 while losing weight and 2.5 for a growing kitten.
Wet food carries a lot of moisture, so each ounce holds fewer calories than kibble does. The daily calories stay the same but the weight needed grows. Enter the kcal per oz from the can and the conversion follows the type you picked.
A cat that eats noticeably less for more than a day, or starts losing weight, needs to be checked promptly because of risks such as hepatic lipidosis. Talk to your veterinarian before adjusting portions on your own.