The amount of calories in popcorn depends on the type of popcorn, how it was popped and if it contains seasonings or butter. Three cups of air-popped popcorn contain around 92 calories.
Air-popped popcorn is the lightest way to prepare popcorn. It is light and fluffy and doesn't contain extra additives like microwave popcorn. For 3 cups of air-popped popcorn with nothing added, there is just over 1 gram of fat, no cholesterol, only 2 mg of sodium, 18.7 grams of carbohydrates, 0.2 gram of sugar and 3.1 grams of protein. There is also a small amount of vitamin A and iron.