Work out how many wallpaper rolls your room needs. Free calculator handles pattern repeats, doors, windows, paste, and liner. Get your roll count fast.
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Ordering wallpaper by square footage alone gets you short. The reason is pattern matching. A wall that’s 108 inches tall with an 18-inch straight-match pattern wastes 18 inches from every strip before you cut the first piece. A half-drop match wastes more. This wallpaper calculator works the way an installer does: it counts strips, not squares. Enter your wall height and perimeter, pick a roll preset, set the pattern type, and the tool returns total strips, strips per roll, and rolls to order with waste built in. Doors and windows get subtracted when you want them deducted. Paste coverage and liner area are calculated from the same inputs.
Pick your unit system. Imperial uses inches, feet, and square feet. Metric uses millimeters, meters, and square meters.
Choose a wall input mode. Perimeter walks the whole room. Single Wall covers one face. Direct Area works if you already know the square footage.
Enter the wall dimensions. For perimeter mode, add room length, width, and height. Pick how many sides you’re papering.
Subtract openings. Enter door and window counts with widths and heights. Toggle the deduct switch if you want them removed from net area.
Choose a wallpaper type. Standard US roll, US double roll, Euro roll, metric roll, wide metric roll, or a custom size.
Set the pattern match type. Random match wastes nothing. Straight match wastes one full repeat per strip. Offset match wastes 1.5 times the repeat.
Enter the pattern repeat. Skip this if you picked random match.
Set your waste factor. 10% covers most rooms. Bump to 15% for heavy cutting.
Choose surface prep and paste. Wall liner, primer, or none. Then set paste coverage per roll.
Add unit costs and read the summary. Rolls to order, paste units, liner area, and total cost all show in the result panel.
Wallpaper math runs on strips, not squares. A strip is one vertical length of paper that runs from ceiling to floor. The number of strips depends on your wall perimeter and the roll width. The strips per roll depends on wall height and usable strip length.
Formula: Total Strips = Ceiling(Wall Perimeter ÷ Roll Width)
Formula: Pattern Allowance = Pattern Repeat × Match Factor
Formula: Usable Strip Length = Roll Length − Pattern Allowance
Formula: Strips per Roll = Floor(Usable Strip Length ÷ Wall Height)
Formula: Rolls Required = Ceiling(Total Strips ÷ Strips per Roll)
Formula: Rolls to Order = Ceiling(Rolls Required × (1 + Waste % ÷ 100))
Match factors come from the pattern type. Random match uses 0. Straight match uses 1 full repeat. Offset match uses 1.5 repeats. The offset figure accounts for cutting strips from alternating positions on the roll so the pattern lines up.
Net area matters for paste and liner, not for roll count. Paste covers roughly five rolls per unit, so a 12-roll job needs three paste units. Liner covers the net wall area. Roll count always uses strips and perimeter, since cutting from a roll wastes the top and bottom of every strip.
Openings matter too. If you deduct a door, the perimeter drops by the door width, which drops the strip count. Most installers deduct openings because papering around a door wastes material. The trade-off is more cutting and more waste. The tool lets you toggle it either way.
A 14-foot by 11-foot bedroom, 8.5-foot ceiling, one 3×7 door, two 4×4 windows. Standard US roll (20.5 in × 33 ft), straight-match pattern with an 18-inch repeat. 10% waste.
Step 1 – Perimeter. 2 × (14 + 11) = 50 ft.
Step 2 – Gross area. 50 × 8.5 = 425 ft².
Step 3 – Openings. Door: 3 × 7 = 21 ft². Windows: 2 × 4 × 4 = 32 ft². Total = 53 ft².
Step 4 – Net area. 425 − 53 = 372 ft².
Step 5 – Total strips. 50 ft ÷ 1.708 ft (20.5 in) = 29.27, rounded up to 30 strips.
Step 6 – Pattern allowance. 18 in repeat × 1.0 (straight match) = 18 in, or 1.5 ft.
Step 7 – Usable strip length. 33 ft − 1.5 ft = 31.5 ft.
Step 8 – Strips per roll. 31.5 ft ÷ 8.5 ft = 3.7, floored to 3 strips per roll.
Step 9 – Rolls net. 30 ÷ 3 = 10 rolls.
Step 10 – Rolls with waste. 10 × 1.10 = 11 rolls.
Step 11 – Paste. At 5 rolls per unit: 11 ÷ 5 = 2.2, rounded to 3 units.
Interpretation: Order 11 rolls of wallpaper. You need 30 strips at 8.5 feet each, and three strips fit on a roll after pattern loss. Three paste units cover the job. If you skipped the door and windows, you’d still be at 11 rolls, since the strip count barely changes. Pattern repeat is the bigger driver here, not openings.
Divide your wall perimeter by the roll width to get total strips, then divide by how many strips fit on a roll. A 50-foot perimeter with a 20.5-inch roll needs 30 strips. At 3 strips per roll, that’s 10 rolls before waste. Add 10% and you’re at 11. Roll count depends on strip geometry, not total square footage.
A standard US roll is 20.5 inches wide and 33 feet long, covering about 56 square feet. A US double roll is the same width but 66 feet long. Euro rolls come in 21 inches × 33 feet. Metric rolls are 0.53 × 10.05 meters. Wide metric rolls are 1.06 × 10.05 meters. Roll sizes vary by region and manufacturer, so check the label before you order.
Measure the perimeter, then multiply by wall height for gross area. Subtract doors and windows for net area. Then convert to strips: perimeter divided by roll width. Strips per roll depends on wall height and pattern repeat. The final roll count is total strips divided by strips per roll, rounded up, plus waste.
The pattern repeat is the vertical distance before the design starts over. An 18-inch repeat means every 18 inches the pattern repeats itself. When you’re cutting strips, you need to align the pattern at the seam, which means the top of each strip may not sit at the ceiling. The mismatch becomes waste at the bottom of the strip.
Straight match lines the pattern up horizontally across each seam. Offset match (also called half-drop) shifts the pattern by half a repeat on alternating strips. Offset wastes more paper but creates a denser look. Random match has no alignment, so nothing is wasted.
Ten percent is standard for a simple room with a random-match paper. Bump to 15% for offset-match patterns. Go to 20% if the room has lots of corners, dormers, or sloped ceilings. The calculator caps waste at 30%, which covers most residential jobs.
Most installers do. Papering around a door or window wastes paper and looks worse at the seams. Deducting them cuts the perimeter, which drops the strip count. The savings are small on a big room but noticeable in a small bathroom with multiple openings.
Paste coverage is usually listed as “rolls per unit” on the package. A standard tub covers about five single rolls. Divide your total rolls by the coverage figure and round up. Ready-mixed paste and powder both follow this rule. Peel-and-stick paper doesn’t need paste at all.
Liner is a plain paper that goes under the decorative wallpaper. It smooths out wall imperfections and makes the top layer easier to remove later. Liner is worth using over textured walls, paneling, or old wallpaper you don’t want to strip. The calculator includes liner area as a separate line item when you toggle it on.
Because the pattern has to line up at every seam. If the pattern repeat is 24 inches and your wall height is 96 inches, each strip has to be at least 96 inches plus up to 24 inches to find the right alignment point. That extra length comes out of the roll, which cuts strips per roll and pushes up the total roll count.
A single roll is 33 feet long. A double roll is 66 feet long. The width is the same on both. Most manufacturers sell double rolls as the smallest unit, which is why “one roll” on a price tag often means a double. Check the length before comparing prices.
Partially. A mural is usually sold as a fixed panel set, not a roll. Enter the mural dimensions in direct area mode and check the net area figure. The roll-based calculations won’t apply since murals don’t come on standard rolls.
Strip-based math catches the pattern loss that square-footage calculations miss.
Match type toggles handle random, straight, and offset patterns without separate tools.
Roll presets load the correct width and length for US, Euro, and metric rolls in one click.
Paste and liner come out of the same inputs, so the materials list stays consistent.
Doors and windows deduct with a single toggle if you want them removed from the net area.
Everything runs in your browser. No accounts, no uploads, no data leaving your machine.
Metric and imperial both work, and all cost fields convert automatically when you switch.
Cost per square foot output makes it easy to compare wallpaper options at different price points.
Divide your wall perimeter by the roll width to get total strips. Divide by how many strips fit per roll. Add 10% waste. A 50-foot perimeter with a 20.5-inch roll needs about 11 rolls with a straight-match pattern.
Measure perimeter, multiply by wall height for gross area. Subtract doors and windows. Then convert to strips and divide by strips per roll. The calculator does all three steps together.
20.5 inches wide by 33 feet long in the US. Euro rolls are 21 inches × 33 feet. Metric rolls are 0.53 × 10.05 meters. Double rolls are the same width but 66 feet long.
10% for random-match paper, 15% for straight match, 20% for offset match. Bump the number higher if the room has many corners or dormers.
Most installers do. Papering around an opening wastes material and creates awkward seams. Deduct the width from the perimeter, and the strip count drops. The calculator handles this automatically when the deduct toggle is on.
The vertical distance before the pattern repeats itself. An 18-inch repeat means the design restarts every 18 inches. Longer repeats waste more paper because more length gets cut off to align the pattern at seams.
Divide total rolls by the paste coverage listed on the package. A five-roll tub covers five single rolls. Round up to the next full unit. Peel-and-stick wallpaper needs no paste.
Straight match lines the pattern up horizontally at each seam. Offset match shifts the pattern by half a repeat on alternating strips. Offset match wastes more paper, about 1.5 times the repeat per strip.
Not always, but liner helps on textured walls, paneling, or old wallpaper you can’t strip. It smooths the surface and makes future removal easier. The calculator adds liner area when you toggle it on.
Partially. Set the wall mode to direct area and enter the ceiling dimensions. The roll math works, but ceilings don’t have perimeter-based strips the same way walls do, so treat the result as a rough estimate.
Strip-based math counts whole strips, not partial ones. If your last strip is only 8 inches wide, it still counts as a full strip from the roll. Pattern matching adds more waste. Rounding up at every step is intentional, since running short mid-install is worse than ordering one extra roll.
Sometimes, but it’s risky. The new paper can pull the old paper loose, and moisture can get trapped between layers. Liner helps but doesn’t solve every case. If the old paper is peeling or has a vinyl surface, strip it first.
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