Wallpaper Calculator

Estimate how many wallpaper rolls you need for a room, allowing for openings and pattern repeat.

Wallpaper Rolls
— rolls
Rounded up.

Usage Tip

Buy all rolls from the same batch (run) number so the color matches, and keep a spare roll for repairs.

THE MATH
wall area = 2 × height × (length + width) − doors × 21 − windows × 15
rolls = round up( wall area × (1 + repeat ÷ 100) ÷ 30 )
Wallpaper is sold in rolls of about 30 usable square feet. The wall area is the perimeter times the height minus the openings, padded by a waste factor for pattern matching.
Enter the room dimensions, the door and window counts, and the pattern repeat in inches.
A larger repeat wastes more at each seam, so it raises the waste factor.
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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.