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Why wallpaper is calculated by strips
Area alone is not enough. Each roll must produce full-height strips, and a repeating pattern can increase the length used by every strip.
Formula
Strips = perimeter ÷ roll width. Adjusted strip = wall height + trim, rounded up to the next pattern repeat. Rolls = strips with waste ÷ strips per roll, rounded up.
Worked example
A 4 × 3 × 2.7 m room has a 14 m perimeter. With a 53 cm × 10.05 m roll, 64 cm repeat, 10 cm trim and 10% extra strips, the estimate is 10 rolls.
Pattern and cutting guidance
- Use the repeat printed on the wallpaper label.
- A straight match and an offset match can consume different lengths.
- Do not subtract ordinary doors and windows for a conservative estimate.
- Keep one unopened roll when future repairs may need the same batch.
FAQ
Wallpaper calculator FAQ
Should I subtract doors and windows?
Usually not for a safe shopping estimate. Cuts around openings still consume full-height strips and create offcuts.
What is pattern repeat?
It is the vertical distance before the design repeats. The value is printed on the roll label and affects each strip length.
Why is the result higher than an area calculation?
Wallpaper is bought as full rolls and cut into full-height strips. Pattern matching and unusable roll ends create extra consumption.
This is a planning estimate. Confirm match type, batch number, roll dimensions and installer allowance before ordering.
About this material
WallpaperBacking types, the symbols on the label, and why roll length tells you almost nothing.