Cat Food Calculator
Enter your cat's weight, lifestyle and the calorie number from the food label. You get daily calories and the portion in cups, computed with the veterinary RER formula.
An estimate based on RER = 70 x (kg ^ 0.75); pounds are converted automatically. Watch your cat's body condition and adjust by ±10%. Not a substitute for veterinary advice.
The formula we use
RER = 70 x (weight in kg ^ 0.75) · MER = RER x factor · cups = MER / kcal per cup Cat factors: growing kitten 2.5, spayed/neutered adult 1.2, intact adult 1.4, very active 1.6, senior 1.1. Per NRC and WSAVA guidelines; sources are on the Methodology page.
Foods in this calorie range
Which foods fit the math, and what to read on the label beyond calories: our guide to choosing a cat food →
Frequently asked questions
How much should a 9 lb cat eat per day?
A spayed or neutered 9 lb indoor cat needs about 240 kcal a day. On a typical 400 kcal/cup dry food that is roughly 0.6 cups. The exact number depends on lifestyle and on your specific food, which is what the calculator asks for.
Does a spayed or neutered cat really eat less?
Yes, noticeably. After spay or neuter the metabolism slows and needs drop by 15 to 20%. If the portion stays the same, the cat gains weight. Pick "spayed/neutered" in the calculator and it applies the lower factor.
Wet or dry food, and how do the numbers compare?
Both can be complete diets. Wet food is about 4 times less calorie-dense per ounce because of the water, so the portions look much bigger. What matters is the calorie number on your label: enter it and the calculator works for either type. A typical 3 oz can is 70 to 100 kcal total.
Why does my cat always beg for more?
Begging is not the same as hunger. Cats naturally eat many tiny meals and often ask for attention, not calories. Stick to the daily total, split into 2 to 3 meals or an automatic feeder. If appetite changes suddenly, in either direction, check with your veterinarian.