Estimate how many rolls of wallpaper you need from your wall area, minus openings, with extra for pattern matching.
rolls = (wall_area − openings) ÷ roll_coverage × (1 + waste)
Subtract openings from the wall area, divide by the coverage per roll, and add waste — patterns need 15% or more for matching.
Large pattern repeats waste more paper. Check the repeat on your roll and increase waste accordingly.
Walls: perimeter 48 ft x 9 ft = 432 square feet. Subtract a door and window, about 40 square feet, for 392 square feet. A standard double-roll covers about 56 usable square feet, so 392 ÷ 56 = 7 rolls before waste, and at 15% pattern-matching waste about 8 rolls.
The waste factor is higher for wallpaper than paint because every strip must align with its neighbor. The bigger the pattern repeat, the more you trim to match — a large repeat can push waste to 20-25%, so check the repeat distance on the roll.
A standard double-roll covers about 56 ft² usable. Pattern matching drives the higher 15% waste — confirm your roll's coverage.
Divide your net wall area by the roll's usable coverage and add 15% for pattern matching.