Wallpaper Calculator: How Much Wallpaper Do I Need?

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Here is the math our wallpaper calculator uses: multiply the total width of the walls by their height, subtract doors and windows, add about 15 percent for pattern matching, and divide by the coverage of one roll. A US single roll covers roughly 28 sq ft and a double roll about 56 sq ft. A 14 ft wide, 8 ft high wall with one opening needs about 4 single rolls (2 double rolls) of a small-pattern paper.

For papers with a large pattern repeat, do the quick strip check further down before you order. It often calls for more.

How many rolls of wallpaper do you need?

Enter the wall size and the usable coverage of one roll.

ft
ft
openings
sq ft
%

A standard US double roll covers about 56 sq ft and a single roll about 28 sq ft before trimming. Use more extra for large pattern repeats.

How to measure for wallpaper

  1. Measure the width of every wall you are papering. Add them together to get the total wall width. For one accent wall, that is just its width.
  2. Measure the wall height. Go from the top of the baseboard to the ceiling or crown molding, which is where the paper will actually go. Measure in a few spots and use the tallest.
  3. Count the doors and windows. The calculator removes about 18 sq ft for each opening. Leave small windows out of the count if you want a safer number.
  4. Find the roll coverage. The label or product page lists the roll width and length. Multiply them to get square feet, and note whether the price is per single or per double roll.
  5. Find the pattern repeat and match type. The repeat is the vertical distance before the pattern starts over. Write it down; you need it for the strip check.

The formula (with a worked example)

  • Wall area = total wall width x height, minus 18 sq ft per door or window
  • Area to cover = wall area x (1 + extra % / 100)
  • Rolls = area to cover / coverage per roll, rounded up

The calculator's default values describe one 14 ft wide wall, 8 ft high, with one opening, 28 sq ft per roll, and 15 percent extra:

  1. Gross wall area: 14 x 8 = 112 sq ft
  2. Minus one opening: 112 - 18 = 94 sq ft
  3. Plus 15 percent: 94 x 1.15 = 108.1 sq ft
  4. Rolls: 108.1 / 28 = 3.86, rounded up to 4

The calculator shows "Buy 4 rolls of wallpaper." and "Wall area: 94 sq ft after openings, plus 15% for pattern matching." Since 28 sq ft is a single roll, that is 2 double rolls. You get the same answer by entering 56 sq ft: 108.1 / 56 = 1.93, which rounds up to 2 double rolls.

Wallpaper: wall area to rollsA 14 foot wide, 8 foot high wall hung with vertical strips of patterned wallpaper. Each strip is cut a little long so the pattern lines up, and the extra is trimmed off. One opening of about 18 sq ft is subtracted: 112 minus 18 is 94 sq ft, plus 15 percent for pattern matching is 108.1 sq ft, divided by 28 sq ft per roll is 3.86, so buy 4 rolls.WALL AREA TO ROLLS−18 sq ftExtra length, trimmed to match the pattern8 ft14 ft of wall112 sq ft14 ft × 8 ft of wall94 sq ftminus one 18 sq ft opening108.1 sq ftplus 15% for pattern match3.86 rolls÷ 28 sq ft per rollBuy 4 rolls3.86, rounded up
A 14 x 8 ft wall with one 18 sq ft opening is 94 sq ft; adding 15% for pattern matching and dividing by 28 sq ft per roll gives 4 rolls.

Check it with a strip count

The area method assumes every inch of the roll ends up on the wall. In practice, you cut the roll into full-height strips, and each strip has to start at the same point in the pattern. Family Handyman recommends working in strips rather than square feet, which builds the pattern repeat into the count:

  1. Strips needed = total wall width in inches / roll width in inches, rounded up
  2. Length of each strip = wall height in inches + pattern repeat
  3. Strips per roll = roll length in inches / strip length, rounded down
  4. Rolls = strips needed / strips per roll, rounded up

Take the same 14 ft (168 in) wall with a 20.5 in x 33 ft (396 in) double roll and a 24 in repeat. You need 168 / 20.5 = 8.2, so 9 strips. Each strip is 96 + 24 = 120 in, so one roll gives 3 strips. Nine strips divided by 3 is 3 double rolls. The door replaces one or two full-length strips, but 7 or 8 strips still take 3 rolls, and you need short pieces above the door as well. So 3 double rolls is the safe order.

That is one double roll more than the area estimate. For large repeats, raise "Extra for pattern match" until the calculator agrees with your strip count. On this wall, with coverage entered as 28 sq ft single rolls, it takes about 50 percent to reach 6 single rolls (3 double rolls).

Strips per double roll by wall height and repeat

Use this chart for the strip check. Each cell shows the number of full strips you get from one double roll: first for a 20.5 in x 33 ft roll, then for a 27 in x 27 ft roll.

Wall heightNo repeat (random match)6 in repeat12 in repeat18 in repeat24 in repeat
8 ft4 / 33 / 33 / 33 / 23 / 2
9 ft3 / 33 / 23 / 23 / 23 / 2
10 ft3 / 23 / 23 / 22 / 22 / 2

Notice how quickly the count drops. A roll that yields 4 strips on an 8 ft wall with a random-match paper yields only 3 once there is any repeat, and a wide 27 in roll with a big repeat yields just 2.

Wallpaper roll sizes

Roll typeTypical sizeCoverage before trimming
Double roll, narrow20.5 in x 33 ftAbout 56 sq ft
Double roll, wide27 in x 27 ftAbout 61 sq ft
Single roll (pricing unit)Half of a double rollAbout 27 to 31 sq ft, depending on the maker

York Wallcoverings produces rolls in both of those widths and notes that each holds about the same square footage. The single roll survives mostly as a pricing unit, so read the listing carefully: a price "per single roll" usually means you must buy in pairs.

Match types and how much they waste

  • Random or free match: strips go up without lining up the pattern at the seams. Grasscloth, stripes, and many textures work this way. Least waste.
  • Straight match: every strip lines up the same way at the ceiling line. Waste depends on the repeat length.
  • Half-drop match: every other strip lines up the same at the top, so the pattern steps diagonally across the wall. Tempaper notes that straight and drop matches waste more than random matches, so round up your order.

Tips and common mistakes

  • Mixing up single and double rolls. If you enter 56 sq ft per roll, the answer is in double rolls. If you enter 28, it is in single rolls.
  • Ignoring the repeat. A big, bold pattern can cost a full extra roll on a single wall. Always run the strip check.
  • Buying from two runs. York assigns each press run its own run number. Order everything at once and check that every roll carries the same run number.
  • Measuring the wrong height. Measure where the paper goes, from the top of the baseboard to the ceiling or crown, not floor to ceiling.
  • Counting on remnants. Leftover pieces rarely fit anywhere except above doors and below windows. Plan full-height strips first.
  • Skipping a spare. Family Handyman suggests adding an extra roll for mistakes. A spare from the same run is also your only reliable patch material later.

Frequently asked questions

How many square feet does a roll of wallpaper cover?

A US double roll is usually 20.5 in x 33 ft (about 56 sq ft) or 27 in x 27 ft (about 61 sq ft). Wallpaper is often priced by the single roll, which is half a double roll, or roughly 27 to 31 sq ft depending on the maker. Wallpapers To Go considers rolls generally 85 to 95 percent usable once you account for cuts, matching, and ends.

How many rolls of wallpaper do I need for a 12 x 12 room?

A 12 x 12 room has 48 ft of wall. At 8 ft high with one door and two windows (about 18 sq ft each), that is 330 sq ft. Adding 15 percent gives about 380 sq ft, or 14 single rolls, which is 7 double rolls. For a large pattern repeat, check the strip count and expect more.

What is the difference between a single roll and a double roll?

York Wallcoverings explains that the single roll became the industry pricing standard, while double rolls became the standard package. So a paper priced "per single roll" is usually shipped as double rolls. Make sure the coverage you enter in the calculator matches the unit you are buying.

Should I subtract doors and windows?

Our calculator subtracts about 18 sq ft per opening. Some retailers, such as Wallpapers To Go, do not subtract openings at all, because trimming around them takes about as much paper as covering them. If your paper has a large repeat, or the openings are small, enter 0 openings for a safer number.

How much extra wallpaper should I buy?

The calculator starts at 15 percent for pattern matching. Random-match papers such as grasscloth or stripes waste the least. Straight and drop matches waste more, and Wallpapers To Go suggests 25 to 70 percent more for patterns that need matching at the seams. When in doubt, use the strip count.

Can I buy one more roll later if I run short?

You can, but it may not match. Each press run gets its own run or lot number, and York recommends ordering from the same run for the best color match. If you cannot, hang the different run on a separate wall so the difference is less visible.