How to calculate wallpaper
Dividing wall area by roll area underestimates, because every strip is cut to the wall height plus trim, and patterned paper wastes extra to line up the design. Counting strips is what installers do.
Example: a 12 × 10 room has 44 ft (528") of wall. With 20.5" wide paper that's 26 strips. For 8 ft walls, each strip is 96" + 4" = 100", rounded up to 105" for a 21" pattern repeat, so a 33 ft (396") double roll gives 3 strips. You need 9 rolls.
Wallpaper tips
- Roll sizes vary. U.S. "double rolls" are often 20.5" × 33 ft; European rolls are about 21" × 33 ft; some designer papers are 27" wide. Use the label.
- Buy one extra roll for repairs and mistakes, all from the same batch or dye lot.
- Pattern repeats over 20" can add a roll or more; a "random match" has no repeat.
Painting the other walls? Use the paint calculator.
Frequently asked questions
How many rolls of wallpaper for an accent wall?
For a 12 ft wide, 8 ft high wall with 20.5" × 33 ft rolls and a 21" repeat, 8 strips at 3 per roll means 3 rolls.
What is a pattern repeat?
The vertical distance before the design repeats. Each strip must start at the same point in the pattern, so longer repeats waste more paper.
Should I subtract doors and windows?
Subtract large openings, like a wide door or picture window. For small windows, the paper above and below still needs strips, so many installers leave them in.
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