Wallpaper Calculator
Calculate wallpaper rolls for any room from wall dimensions, roll size, and pattern repeat.
Returns roll count with waste for standard and double rolls.
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.
Standard roll sizes by region
| Roll type | Width | Length | Coverage |
|---|---|---|---|
| US single roll | 27 in | 27 ft | ~60.75 sq ft |
| US double roll (common retail) | 27 in | 54 ft | ~121.5 sq ft |
| Euro roll | 20.5 in | 33 ft | ~56.4 sq ft |
| Wide roll (commercial) | 36–52 in | varies | varies |
In US home centers, what’s labeled “one roll” is almost always a double roll. Check carefully; labeling varies between sellers, and buying based on the wrong assumption can leave you 50% short.
Waste factor by pattern type
| Pattern type | Typical waste |
|---|---|
| No pattern / random match | ~10% |
| Straight match, small repeat (under 6") | ~15% |
| Straight match, large repeat (12"+) | ~25% |
| Drop match (offset by half repeat) | ~20–30% |
The pattern repeat costs you length on every strip because each strip after the first must align with its neighbor. A 24-inch repeat on a 9-ft wall wastes about 24 inches per strip, almost 25% loss before counting offcuts around doors and windows.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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