How many calories in powdered sugar?

15 calories.

There is 16oz or 4 cups in a box of powdered sugar.

There are 8 oz in a cup 16 oz in a pound ... that applies to liquid water, not powdered sugar. There are approximately 3 3/4 cups of Powdered sugar in a pound.

There are varieties of sugar. Maple sugars contains 1,481 kilojoules per 100g (419 cals per oz) and Turbinado sugar has 1,670 kilojoules per 100g (473 cals per oz), for instance. A normal value is...

15 calories per teaspoon.