Find how many wallpaper rolls your wall needs. Enter wall and roll sizes plus pattern repeat to get wall area, strips needed, and rolls with a 10% waste allowance.
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Wallpaper is not sold by the square foot, it is sold in rolls that you cut into full-height strips, also called drops. A roll only covers your wall when its printed length divides cleanly into strips tall enough to reach from baseboard to ceiling. To calculate the roll count, this calculator converts your wall and roll measurements to inches, figures out how many strips each roll yields after allowing for the pattern repeat, and counts how many strips it takes to span the wall width. It then adds a 10 percent waste allowance for trimming and mistakes, and rounds up to a whole roll, because you cannot buy part of a roll and running short mid-project forces a reorder from a different batch.
Most people estimate wallpaper by dividing wall area by roll area, and that is why they run short. The area method ignores the real constraint: each roll must be cut into full-height strips, and any length left over after the last full strip is waste you cannot use. The strip method used here is what professional decorators work with. First, convert everything to inches so roll width and wall width share a unit. The strip height is your wall height plus the pattern repeat, because each new strip must be shifted so the design lines up with the previous one. Dividing the roll length by the strip height, rounded down, gives strips per roll. Dividing the wall length by the roll width, rounded up, gives strips needed. The final roll count adds 10 percent waste and rounds up. If the pattern repeat is so large that not even one full strip fits a roll, the calculator still counts 1 strip per roll rather than dividing by zero.
Measure the wall you plan to paper: length along the floor and height from baseboard to ceiling, both in feet. If you are doing several walls, add their lengths together and use the tallest height. Then read your wallpaper label for the roll width in inches, roll length in feet, and pattern repeat in inches. Enter 0 for pattern repeat on plain, striped, textured, or random-match papers. The calculator returns your total wall area, how many full-height strips the job needs, and how many rolls to buy. Buying one spare roll beyond the result is common practice: batches are printed separately and a later reorder can look slightly different on the wall. For a bedroom, measure all four walls and treat the result the same way; for a single feature wall, just enter that wall's length and the tallest height.
The pattern repeat is the vertical distance between two identical points in the design, printed on the label as something like a 21 in vertical repeat. It matters because adjacent strips must line up so the pattern continues unbroken across the seam. A plain or random-match paper has no repeat, so you can start each cut anywhere and waste almost nothing. A straight match repeats at the same height on every strip, wasting up to one repeat per strip. A half-drop (or drop match) shifts the pattern down by half the repeat on alternating strips, which usually wastes a little more than a straight match of the same size. Large repeats of 24 in and more are common on botanicals and damasks and can raise the roll count by 20 to 30 percent compared with plain paper.
The most common roll in the US is the double roll, 20.5 in wide and 33 ft long, covering about 56 square feet, though pricing is often quoted per single roll. Single vs double wallpaper roll is a common point of confusion: a single roll is simply half a double roll, so the standard US double roll yields two single rolls' worth of strips. The standard European roll is 21 in (53 cm) wide and 33 ft (10.05 m) long, close to the same coverage. Wide-width designer papers run around 27 in wide, and commercial vinyl comes in much wider and longer rolls. Peel-and-stick panels are often sold by the panel rather than by the roll, with widths like 19 to 25 in and preset heights. Because sizes vary so much, never trust the word standard: always use the width, length, and repeat printed on your label, or the calculator result will be wrong.
Take a 12 ft long, 8 ft high wall with a 21 in wide, 33 ft long roll and no pattern repeat. Wall area is 12 × 8 = 96 sq ft. In inches the wall is 144 in long and 96 in high, and the roll is 396 in long. Strip height is 96 + 0 = 96 in, so strips per roll is floor(396 / 96) = 4. Strips needed is ceil(144 / 21) = 7. Rolls needed is ceil(7 × 1.10 / 4) = ceil(1.925) = 2 rolls. Now add a 12 in pattern repeat: strips per roll becomes floor(396 / 108) = 3, and the roll count becomes ceil(7 × 1.10 / 3) = ceil(2.5667) = 3 rolls. That one extra roll is the cost of the pattern. As a rule of thumb, a 12x12 room with 8 ft ceilings needs about 6 to 8 rolls of plain paper, or 8 to 10 rolls with a 12 in half-drop pattern, depending on doors and windows.
Even a perfect calculation cannot predict every real-world cut. Walls are rarely perfectly square, so strips cut for the tallest point leave waste on shorter runs. Corners, outlets, and radiators force extra pieces. Beginners miscut, and experienced decorators still trim a couple of inches top and bottom on every drop. Ten percent covers plain papers on straightforward walls; patterned papers with large repeats deserve more like 20 percent, which the repeat math already produces for you. Rounding up to whole rolls plus the allowance means you finish the job with a little left over, which is exactly what you want for future repairs from the same batch. The right percentage to add depends on the paper: plain and random match stay at 10 percent, small repeats take about 15 percent, and large repeats take 20 percent or more.
Pattern repeat is the vertical distance between two identical points in the design, printed on the roll label. Each strip must be offset so the pattern lines up with its neighbor, which wastes paper. Larger repeats waste more and raise the number of rolls you need.
This calculator adds a 10 percent waste allowance for trimming, crooked walls, and mistakes. For plain paper on a simple wall that is enough. For large pattern repeats of 24 in or more, expect 20 to 30 percent more rolls than plain paper, and always buy one spare roll for future repairs.
Do not deduct small windows, because the offcuts above and below them are too short to reuse. For a standard door or a large bay window, deducting about half the opening area is reasonable. When in doubt, keep the extra paper rather than risk running short mid-project.
With a straight match the pattern lines up horizontally at the same height across every strip, which is easy to hang with moderate waste. With a half drop, also called drop match, the pattern on alternating strips shifts down by half the repeat, creating a flowing diagonal effect but usually wasting more paper than a straight match of the same repeat size.
The common US double roll is 20.5 in wide and 33 ft long, about 56 sq ft per single roll, though prices are often quoted per single roll. The European standard is 21 in (53 cm) wide and 33 ft (10.05 m) long. Wide-width designer and commercial papers differ, so always check the label on the paper you are buying.
Wallpaper is printed in production batches, and each batch can have slight color variations from ink mixing and dye differences. If you run short and reorder from a different batch, the new strips can look visibly different beside the old ones. Always buy all rolls from the same batch, plus a spare.
Divide the roll length by the strip height (wall height plus pattern repeat) and round down. With a standard 33 ft roll and an 8 ft wall, that is 4 strips for plain paper, 3 with a 12 in repeat, and 2 with a 24 in repeat. Taller walls or larger repeats always reduce the strip count.
Most wallpaper in the US is sold as double rolls but priced per single roll, which confuses many buyers. This calculator asks for the roll length in feet, so enter the actual length of the roll you are buying (33 ft for a single roll length, 66 ft for a double). The result is the number of those rolls you need.