Wallpaper Calculator

A single roll typically covers about 28 sq ft of wall; a double roll, the standard sold at most US retailers today, is twice as long and covers roughly 56 sq ft. Double rolls waste fewer strips because more full-length cuts fit without seaming mid-roll. This calculator lets you enter your actual roll length and width, so the math works for any roll size you buy.

A pattern repeat is the vertical distance before the design restarts. Each strip gets cut up to the next full-repeat increment so adjacent strips align. With a 24-inch repeat on an 8 ft (96-inch) wall, every strip rounds up to 96 inches, leaving no waste. On a 9 ft (108-inch) wall, each strip rounds up to 120 inches, wasting 12 inches per strip, which can add one or two rolls to your order.

Start in an inconspicuous spot, typically the corner behind the main entry door, and work around the room in one direction. The final strip will meet the first, so any small pattern mismatch lands where it is least visible. Hang each strip from ceiling to floor and trim the excess at the baseboard.

The calculator subtracts 21 sq ft per door (a standard 3 ft x 7 ft opening) and 15 sq ft per window (3 ft x 5 ft) from the displayed wall area. Roll and strip counts still assume full-perimeter strips, though, because you cut a strip at every opening and the scraps are not reusable. Use the wall area figure to cross-check against a roll's coverage spec, not to compute rolls directly.

Trimming at ceilings and baseboards, correcting misaligned strips, and the occasional damaged section all consume extra paper. The 10% buffer also guards against dye-lot variation: wallpaper printed in different batches can show subtle color shifts, so you want enough from one lot to finish the job without a second order.