1. Calculate the perimeter of the room
2. Multiply the perimeter by the height of the walls to be covered to get the total amount of area required in square feet
3. Add 20% for waste to the total
4. Calculate the total area of doors, windows and other features that will not be covered. Deduct 15sf for ONE door or TWO windows is a common rule of thumb
5. Subtract the area in STEP 4 from the area in STEP 3. This is the total area of wallpaper needed.
6. Divide the area per roll of wallpaper into the area found in STEP 5 to determine the number of rolls needed.
Total Area Square Footage/36sf= X rolls
*A roll of 27" wide wallpaper contains 36sf. The more commonly used double roll contains 72sf.