How to work out how many rolls you need
Dividing the wall area by the square feet on the label gives too few rolls. Wallpaper is hung in full-height strips, and every strip has to start at the same point in the pattern, so the leftover at the end of each roll is often too short to use. Installers count strips instead. Here is that method with the values the calculator opens with: a 12 x 10 room with 8 ft walls, one door, two windows, standard 20.5 inch double rolls and a straight match with a 21 inch repeat.
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1
Measure the width you will cover
The perimeter is (12 + 10) x 2 = 44 ft, or 528 inches. Take off 36 inches for the door. Windows still need short strips above and below, so take off only half of each one, 18 inches. 528 − 36 − 36 = 456 inches.
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2
Count the strips
Divide by the roll width and round up: 456 ÷ 20.5 = 22.2, so 23 strips.
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3
Find the cut length
Add 4 inches to the wall height for trimming, 2 at the ceiling and 2 at the baseboard: 96 + 4 = 100 inches. With a repeat, round up to a whole number of repeats so each strip starts at the same spot: 100 ÷ 21 = 4.8, so 5 repeats, or 105 inches.
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4
See how many strips one roll gives
A 33 ft roll is 396 inches long. 396 ÷ 105 = 3.8, and only whole strips count, so 3 strips per roll.
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5
Divide and round up
23 strips ÷ 3 per roll = 7.7, so 8 rolls. Add one spare from the same batch and buy 9 double rolls.
The wall itself is 301 sq ft (44 x 8 = 352, less 21 for the door and 15 per window). Nine rolls hold about 500 sq ft of paper, so you will throw away a lot of offcuts. That is normal: the area method would have said 6 rolls and left you five strips short. At the default prices, 9 rolls at $60, a gallon each of paste and primer, and a basic tool kit come to $653. An installer at $4 per sq ft adds $1,204 in labor.
Wallpaper roll sizes
Most wallpaper sold in the US today is priced and sized as a double roll, about 20.5 inches by 33 feet. European rolls are almost the same size. Some older American patterns still come 27 inches wide, and peel-and-stick rolls are usually shorter. Always check the label.
| Roll | Size | Paper | 8 ft strips |
|---|---|---|---|
| US double roll | 20.5 in x 33 ft | 56 sq ft | 3 |
| Euro roll | 53 cm x 10.05 m | 57 sq ft (5.3 m²) | 3 |
| Wide double roll | 27 in x 27 ft | 61 sq ft | 3 |
| Peel-and-stick | 20.5 in x 18 ft | 31 sq ft | 2 |
Strip counts assume 8 ft walls, a 21 inch straight repeat and 4 inches of trim. Some stores still quote prices per single roll and sell only in double rolls, so a "$30 roll" can mean $60 for what you take home. Compare the price per square foot of paper, not per roll.
Pattern repeat and match
The repeat is how far down the strip you go before the design starts over. A small repeat wastes little. A large one can cost you a strip per roll, especially on walls just over 8 or 9 ft, where the cut length jumps by a whole repeat.
| Repeat, straight match | Cut at 8 ft | Strips per roll | Cut at 9 ft | Strips per roll |
|---|---|---|---|---|
| None (random) | 100 in | 3 | 112 in | 3 |
| 10.5 in | 105 in | 3 | 115.5 in | 3 |
| 21 in | 105 in | 3 | 126 in | 3 |
| 25 in | 100 in | 3 | 125 in | 3 |
| 27 in | 108 in | 3 | 135 in | 2 |
For 20.5 inch, 33 ft rolls. Note the 27 inch repeat on a 9 ft wall: the cut jumps to 135 inches and each roll drops to 2 strips, so the job needs a third more paper. On a straight match the design lines up straight across the seam. On a half-drop every other strip starts half a repeat lower, so the calculator adds half a repeat to each cut. Random papers (stripes, grasscloth, textures) need no matching at all, though grasscloth makers often ask you to reverse every other strip.
Rolls for common room sizes
8 ft walls, one door, two windows, standard double rolls, 21 inch straight repeat, one spare roll included. Tap a size to load it into the calculator.
| Room | Wall area | Strips | Rolls to buy |
|---|---|---|---|
| 5 x 8 powder room | 157 sq ft | 12 | 5 |
| 10 x 10 | 269 sq ft | 20 | 8 |
| 10 x 12 | 301 sq ft | 23 | 9 |
| 12 x 12 | 333 sq ft | 25 | 10 |
| 12 x 14 | 365 sq ft | 27 | 10 |
| 14 x 16 | 429 sq ft | 32 | 12 |
| 12 ft accent wall | 96 sq ft | 8 | 4 |
The accent wall row is a plain 12 x 8 ft wall with no door or window: 144 inches of width is 8 strips, which is 3 rolls plus the spare. One wall is the best first project: the corners and the ceiling line are the hard part, and a single wall has few of both.
What it costs: DIY vs. hiring an installer
Paper prices run from about $25 a roll for simple printed paper to $150 for heavy non-woven designer lines, and well over $100 for grasscloth, silk or specialty finishes. Installers usually price by the square foot of wall: about $2 to $6 for standard paper and $6 to $14 for grasscloth, murals and hard rooms. Many also quote per roll or by the hour, and removing old paper first adds about $1 to $3 per sq ft.
| Job | DIY total | Installer labor |
|---|---|---|
| 12 ft accent wall | $353 | $190–$580 |
| 5 x 8 powder room | $413 | $310–$940 |
| 10 x 12 bedroom | $653 | $600–$1,810 |
| 14 x 16 living room | $893 | $860–$2,570 |
DIY totals are this calculator at its defaults ($60 rolls with a spare, paste, primer and tools). Labor is $2 to $6 per sq ft of wall, paper not included. A powder room costs more per square foot than a bedroom because of the toilet, the vanity and all the cutting around them. Tall stairwells, ceilings, murals and real grasscloth are worth handing to a pro: seams show on grasscloth, and a mural that drifts out of plumb cannot be fixed.
Tips from the trade
- Prime first. A wallpaper primer seals the drywall so paste does not soak in, gives the paper "slip" while you slide it into place, and lets the paper come off later without tearing the drywall face.
- Check every label before you cut. Batch or lot numbers should all match. Unroll a few feet of each roll in good light to look for printing flaws.
- Hang the first strip on a plumb line, not off a corner or a door frame. Corners are rarely straight, and every strip after the first follows its mistakes.
- Start where a mismatch will hide. The last strip almost never matches the first. Plan for that seam to land in a corner behind a door or above a door.
- Book the paste. Pre-pasted and some traditional papers must rest folded paste to paste for a few minutes before hanging. Follow the label; skipping it causes bubbles and shrinking seams.
- Don't overlap seams unless the label says to. Butt them tight and press them with a seam roller. Wipe paste off the face right away with a damp sponge.
- Turn off the power before trimming around outlets and switches, and take the cover plates off first.
Peel-and-stick paper skips the paste but not the prep: it needs a clean, smooth, fully cured painted wall to hold. On fresh paint, makers usually ask you to wait several weeks. It is a good choice for renters and accent walls; for a whole room with humid air, like a bathroom, traditional paper and the right paste hold better.
Common questions
How many rolls of wallpaper do I need for a 12x12 room?
A 12x12 room with 8-foot walls, one door and two windows needs about 25 strips of standard 20.5-inch paper. A 33-foot double roll gives 3 full-height strips, so buy 9 double rolls, or 10 with a spare from the same batch.
How many square feet does a roll of wallpaper cover?
A standard US double roll (20.5 inches by 33 feet) and a European roll (53 cm by 10 m) each hold about 56 to 57 square feet of paper. After trimming and matching the pattern you usually hang 40 to 50 square feet from it, and less on tall walls or with a large repeat.
What is a pattern repeat?
The pattern repeat is the distance before the design starts over, printed on the label in inches or centimeters. Each strip has to start at the same point in the pattern, so a large repeat means longer cuts, fewer strips per roll and more rolls to buy.
What is the difference between a straight match and a half-drop match?
With a straight match the design lines up straight across from one strip to the next. With a half-drop match every other strip drops by half a repeat, so you waste a little more on each cut. Random-match papers, such as stripes and textures, have no repeat to line up.
Should I buy an extra roll of wallpaper?
Yes. Rolls are printed in batches, often called dye lots, and a roll from a later batch can be a slightly different color. One spare roll from the same batch covers a miscut strip and future repairs.
How much does it cost to wallpaper a room?
Doing it yourself in a 12x10 bedroom costs about $650 with $60 rolls, paste, primer and tools. An installer charges about $2 to $6 per square foot for standard paper and $6 to $14 for grasscloth or murals, so the same room costs about $1,800 with labor and paper.
Sources and assumptions
The roll count is plain geometry, done strip by strip. Prices are typical US prices checked in October 2026; they vary a lot by brand and region, and the roll price and installer rate can both be edited.
- Roll sizes: the 20.5 inch x 33 ft double roll of about 56 sq ft and the roughly 53 cm x 10 m European roll, as listed by wallpaper sellers such as Selected Wallpapers (European rolls vs. double rolls) and the DecoratorsBest wallpaper guide. The peel-and-stick size (20.5 in x 18 ft) is a common size, not a standard; check your label.
- Paper prices ($25 to $150 per roll for most papers, more for grasscloth and silk) come from the Inch Calculator wallpaper cost guide and the Taskrabbit wallpapering cost guide (October 2026).
- Installer rates ($2 to $6 per sq ft for standard paper, $6 to $14 for grasscloth and murals, $1 to $3 per sq ft to remove old paper) are from the same Taskrabbit guide. Inch Calculator reports $4 to $10 per sq ft installed, paper included.
- Paste and primer: clear wallpaper adhesive covers up to about 330 sq ft per gallon and pigmented wallpaper primer about 400 to 450, per Roman's technical data sheets for PRO-880 adhesive and PRO-977 primer. The calculator plans 330 and 400 sq ft per gallon and prices them at $25 and $35 a gallon, which are estimates of typical shelf prices.
- Counting rules: 4 inches of trim per strip; doors take 36 inches off the width and windows 18 inches (half, since short strips go above and below them); the wall area subtracts 21 sq ft per door and 15 sq ft per window. A half-drop match adds half a repeat to every cut. These are common installer rules of thumb, not a standard.
- Tools: a smoother, seam roller and sponge ($15), a snap-off knife with spare blades ($10), a 6 inch taping knife as a trim guide ($8), a chalk or laser line ($8) and, with paste, a roller and tray ($12). These are estimates.