Why indoor and outdoor cats feed differently
The calculator starts with resting energy requirement and then applies a maintenance factor based on life stage and lifestyle. Kittens need more calories relative to body weight because they are growing. Adult cats usually need less, but indoor-only cats often need a lower starting intake than outdoor or mixed-lifestyle cats that spend more energy moving and thermoregulating.
That lifestyle distinction matters because cat-food labels often give a broad feeding range that cannot fully capture whether a cat is sedentary indoors or burning through calories outside. A calorie-based estimate gives you a cleaner starting point before you translate that into cups or grams from the food label.
RER = 70 × weight(kg)^0.75
Resting energy requirement is the baseline before kitten, adult, or senior lifestyle factors are applied.