To calculate the square footage of your space, we recommend combining the width of each wall, then multiplying this number by your ceiling height. Next, divide this number by the square footage of a single roll of wallpaper to determine the number of rolls required. Always round up to account for pattern repeat and variation. Need help choosing the right wallpaper for your home? Read our guide to transforming your walls - and your space. Clark Plaid Wallpaper by Mitchell Black in Green at Anthropologie