Wallpaper Roll Calculator
Wondering how many rolls of wallpaper do I need for your project? Measure your walls, subtract doors and windows, and this free calculator tells you the exact number of rolls to buy — with pattern-repeat waste built in so you never run short mid-wall.
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Enter your wall sizes to see how many rolls you need.
How to use this calculator
Choose “Whole room” if you are papering all four walls, or “Single wall” for an accent wall. Measure length, width, and height in feet — a tape measure and a minute are all you need. Wall height is measured from the top of the baseboard to the ceiling.
Enter the number of doors and windows on the walls you are papering. The calculator subtracts 21 sq ft per door and 15 sq ft per window, which are standard rough estimates. If a window is unusually large, count it as two.
Set the coverage per roll from your roll's label — 56 sq ft is the standard US double roll. Set pattern-repeat waste to 0% for solid or random-match papers, 10–15% for typical patterns, and 15–20% for large repeats that force big trims off every strip. Results update instantly as you type.
How it works
For a whole room, total wall area is the perimeter times the height: wall area = 2 × (length + width) × height. For a single wall it is simply wall area = wall width × wall height.
Then openings are subtracted: openings = doors × 21 + windows × 15 (sq ft), and the net area is floored at zero: net area = max(wall area − openings, 0).
Finally, the waste allowance is added and the result is divided by the coverage per roll, always rounding up to the next whole roll: rolls = ceil(net area × (1 + waste ÷ 100) ÷ coverage). For example, a 12 ft × 8 ft wall is 96 sq ft; with a 56 sq ft roll and no waste, 96 ÷ 56 = 1.71, so you buy 2 rolls.
The pattern-repeat waste is an honest estimate, not an exact count. Real waste depends on the repeat size and your wall height: a small repeat trims little off each strip, while a large repeat can force you to cut off nearly a full repeat from every strip. Solid papers and random matches waste almost nothing; bold large-scale patterns waste the most. If your pattern has an unusually large repeat, use the 15–20% end of the range and buy one spare roll.
Estimate based on standard assumptions: 21 sq ft per door, 15 sq ft per window, US double roll of 56 sq ft. Actual coverage varies by brand and pattern — always check your roll's label.
Frequently asked questions
How many rolls of wallpaper do I need?
Measure the walls you plan to cover, subtract doors and windows, then divide the total wall area by the usable coverage per roll and round up. For example, a single 12 ft by 8 ft wall is 96 sq ft; with a standard US double roll covering 56 sq ft and no pattern waste, 96 divided by 56 equals 1.71, so you need 2 rolls.
Why does the calculator add pattern-repeat waste?
Wallpaper patterns must line up from strip to strip, so part of every drop is trimmed off to match the repeat. A larger repeat means more trimming. Adding 10 to 15 percent extra for waste keeps you from running short, and solid or random-match papers need the least.
Should I subtract doors and windows?
Yes. This calculator subtracts 21 sq ft per door and 15 sq ft per window, which are standard rough estimates. If your doors or windows are much larger or smaller, adjust the counts to compensate — for example, count a large picture window as two.
How much does one roll of wallpaper cover?
A standard US double roll covers about 56 sq ft and a single roll about 28 sq ft. European rolls are narrower and cover roughly 53 to 57 sq ft. Always check the label on the roll you are buying, because coverage varies by brand and pattern.
Should I buy an extra roll?
Yes. Dye lots vary between production batches, so paper from a second purchase may not match perfectly. One spare roll is the standard recommendation, and this calculator already rounds up to the next whole roll on top of your pattern-repeat waste allowance.