Calculate how many rolls of wallpaper you need for a room. Enter the room dimensions, wall height, number of doors and windows, roll type and pattern repeat to get an accurate roll count that accounts for all common sources of waste.
Assumes avg door 3×7 ft (21 sq ft) and window 3×5 ft (15 sq ft).
Pattern repeat adds extra waste: 0% for plain, ~15–25% for large repeating patterns.
Enter room dimensions to calculate.
Wall area is calculated from room perimeter and height, then openings are deducted:
Paintable Area = (2 × (L + W) × Height) − (Door + Window Area)
The result is divided by the usable coverage per roll. Pattern repeat adds extra waste because each drop must be aligned — a 24-inch repeat wastes on average half the repeat length per strip. Always buy one extra roll for repairs and future touch-ups.
Always confirm the exact roll dimensions with the manufacturer before ordering — sizes vary significantly between brands.
Pattern repeat is the vertical distance between identical motifs on the wallpaper. It directly affects how much waste is generated matching strips:
Measure the perimeter of the room (all four walls), multiply by the ceiling height to get gross wall area in sq ft. Subtract 15 sq ft per door and 10 sq ft per window. Divide by the usable coverage per roll and add 10% for waste.
Feature walls (one wall) are more forgiving for first-timers and reduce material cost by 75%. They work especially well with bold patterns or textured wallpaper that would be overwhelming on all four walls.
This is not recommended — the extra weight can cause both layers to peel, seams telegraph through and new adhesive may not bond well. Strip existing wallpaper and properly prep the wall with primer before hanging new paper.