how to calculate how much wallpaper you need?
['For example, if your total surface area is 480 square feet (45 m2) and each roll gives you 25 square feet (2.3 m2) of usable wallpaper, then 480/25 = 19.2.', 'Round the answer up to the nearest number. ... ', 'Wallpaper is sold in single and double rolls.']