Wallpaper Calculator

Wallpaper estimation requires measuring the total wall area, accounting for pattern repeat (which causes waste), subtracting doors and windows, and converting to the number of rolls based on the usable coverage per roll.

Core formula: Total Wall Area = Perimeter × Wall Height (minus doors and windows) Strips per Roll = Roll Length / (Wall Height + Pattern Repeat) Rolls Needed = Number of Strips / Strips per Roll × Waste Factor

What each variable means:

• Perimeter — total distance around the room (sum of all wall widths); includes walls that have doors/windows since you cut around them
• Wall Height — floor to ceiling; measure in the same units as the roll length (usually meters in European rolls, feet in US rolls)
• Pattern Repeat — the vertical distance between identical points in the wallpaper design; extra length is wasted matching patterns between strips; no repeat (solid/texture) = 0 waste
• Strips per Roll — how many full-height strips you can cut from one roll accounting for pattern matching
• Standard roll coverage — European double rolls cover approximately 56 ft² (5.2 m²); US single rolls cover ~34 ft² (3.1 m²)
• Waste Factor — 10% for simple patterns; 15–25% for large pattern repeats (e.g., 24" repeat wastes significantly)

Worked example: Room: 15’ × 12’, ceiling height 9’. Two doors (3’ × 7’), two windows (3’ × 4’). Wallpaper has a 12" (1 ft) pattern repeat. Roll length: 27 ft (standard US double roll = 27 ft × 2 ft wide).

Total perimeter = 2 × (15 + 12) = 54 linear feet Wall strips needed: 54 / 2 = 27 strips (at 2 ft wide per strip) Strip length needed per strip: 9 ft (height) + 1 ft (pattern repeat) = 10 ft Strips per roll: ⌊27 / 10⌋ = 2 strips per roll (27 ft roll / 10 ft strip) Rolls needed: 27 strips / 2 = 13.5 → 14 rolls Subtract openings (doors + windows subtract ~3–4 strips total): ~11–12 rolls net, order 14

Always order extra — dye lots vary between production runs, and discontinued patterns become unavailable.