No need to question how many cups are in a pound of granulated sugar, brown sugar, or powdered sugar. We've got cup measurements for one pound of each.
A pound of powdered sugar contains approximately 4 cups.
A pound of brown sugar -- light or dark -- contains about 3-1/2 cups when loose and 2-1/4 cups when packed. Packed brown sugar is called for in most recipes.
A pound of granulated sugar contains approximately 2 cups.