Measure once. Order right.
A visual reference for sizing wallpaper rolls, wall murals and full rooms — formulas, diagrams and examples in one place.
The two formulas.
Always round up.
Add 2" on the right and top for trim — that's it.
Wallpaper rolls.
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01
Measure wall width
Top, middle, bottom. Use the largest.
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02
Calculate rolls
108"÷20"=5.4→6 rollsRound UP to the next whole number.
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03
Measure wall height
Floor to ceiling at multiple points. Use the tallest. Add a few cm/inches for trimming.
Example=96" (244 cm) -
04
Choose roll size
Standard roll heights:
40"102 cm60"152 cm80"203 cm100"254 cm120"305 cm150"381 cmTraditional rolls: Single Roll 5 m, Double Roll 10 m.
Order 1 extra roll as a safety buffer for doors, windows, or first‑time installation.
Wall murals.
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01
Measure width
Top, middle, bottom. Largest wins.
-
02
Measure height
Multiple points across the wall. Use the tallest. Include baseboards or crown molding if covering.
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03
Calculate area
Width×Height=AreaImperial12 ft×9 ft=108 sq ftMetric3.6 m×2.7 m=9.72 m²Inches → divide by 144 for sq ft. Centimeters → divide by 10,000 for m².
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04
Add 2" trim margin
Add 2 inches (5 cm) on the right side and on the top only. That's enough trim allowance — no need for 10–15% extra area.
+ 2" Right side+ 2" Top
Doors, windows & obstacles.
Standard doors
Don't subtract. You'll need wallpaper around the door frame.
No subtractionSmall windows
Don't subtract. Windows under 3 × 3 ft don't significantly affect your order.
Under 3 × 3 ftLarge / picture windows
Subtract 50% of large window area. Larger than 3 × 3 ft → subtract half.
Subtract 50%When in doubt, don't subtract anything. Having a little extra is always better than running short.
Full room.
Measure each wall separately, add a 2" trim margin to the width and height of each, then sum.
Imperial
4‑wall room| Wall 1 | 12 ft × 9 ft | 108 sq ft |
|---|---|---|
| Wall 2 | 10 ft × 9 ft | 90 sq ft |
| Wall 3 | 12 ft × 9 ft | 108 sq ft |
| Wall 4 | 10 ft × 9 ft | 90 sq ft |
Metric
4‑wall room| Wall 1 | 3.6 m × 2.7 m | 9.72 m² |
|---|---|---|
| Wall 2 | 3.0 m × 2.7 m | 8.10 m² |
| Wall 3 | 3.6 m × 2.7 m | 9.72 m² |
| Wall 4 | 3.0 m × 2.7 m | 8.10 m² |
Common mistakes.
Measuring only once
Walls are rarely perfectly square.
Forgetting the extra
The most common mistake.
Subtracting every opening
Don't subtract all doors and windows.
Mixing units
Stick to one unit throughout.
Unit conversions.
Length
- 1 foot12 inches
- 1 foot30.48 cm
- 1 meter3.28 feet
- 1 inch2.54 cm
Area
- 1 sq ft144 sq inches
- 1 sq ft0.093 m²
- 1 m²10.76 sq ft
- 10 sq ft≈ 1 m²
FAQ.
What if my walls aren't perfectly straight?
Measure multiple points and use the largest. The 2" trim margin on the right and top covers small irregularities.
Floor or top of baseboard?
Measure to the floor if you're wallpapering behind the baseboard, or to the top of the baseboard if trimming there. Leave 1–2 inches extra either way.
What about pattern matching?
The 2" trim margin gives enough room for clean alignment. For very large or complex patterns, ask us first and we'll plan the layout for you.
What if I have too much wallpaper?
Keep extras for future repairs. Store rolled in a cool, dry place.
How do I measure for an accent wall?
Same way — width × height with a 2" trim margin on the right and top.
Ready to order?
Open the customizer and enter your wall size — we'll print to fit.