Wallpaper Calculator: How Many Rolls Do I Need?

This wallpaper calculator estimates how many rolls you need for an accent wall or a whole room, based on the total wall width, the wall height, the doors and windows you will paper around, the pattern repeat and the roll size. It adds a trim and matching allowance automatically, so the result is the number of rolls to buy rather than a bare area.

Wallpaper Calculator

Estimates only. Check product labels and local conditions before buying.

How to Use the Wallpaper Calculator

  1. Measure the width of each wall you plan to paper in feet and add them together. For a full room, this is the room’s perimeter.
  2. Measure the wall height from the floor (or the top of the baseboard) to the ceiling.
  3. Count the doors and windows on those walls.
  4. Choose the pattern repeat listed on the roll label. Pick “None or random” for plain papers, grasscloth and random match designs.
  5. Choose the roll size. Many American papers are sold as double rolls of about 56 square feet, while European rolls cover about 57 square feet. Then read the rolls to buy.

How the Calculation Works

The calculator multiplies the total wall width by the wall height to get the gross wall area. It then subtracts 20 square feet for each door and 15 square feet for each window, which are standard allowances for a typical interior door and an average window. If the openings add up to more than the wall, the area is set to zero.

Next it adds an allowance for trimming and pattern matching that depends on the repeat you select: 10% for no repeat or a random match, 15% for repeats up to 6 inches, 20% for repeats of 7 to 18 inches, and 25% for repeats over 18 inches. Larger repeats waste more paper because each strip has to be shifted up or down to line up with the one beside it. The paper needed is divided by the roll coverage (56, 28 or 57 square feet) and rounded up to a whole roll.

Worked example with the default values: 12 feet of wall, 8 feet high, no doors, 1 window, a small repeat (up to 6 inches) and double rolls of 56 square feet.

  • Wall area: 12 x 8 = 96 square feet
  • Openings: 0 doors x 20 + 1 window x 15 = 15 square feet
  • After doors and windows: 96 – 15 = 81 square feet
  • Pattern and trim allowance: 15% for a small repeat
  • Paper needed: 81 x 1.15 = 93.15, shown as 93 square feet
  • Rolls: 93.15 / 56 = 1.66, rounded up to 2 rolls

For a full 12 x 12 foot room (48 feet of wall) with 8 foot walls, 1 door and 2 windows, the paper needed is 334 x 1.15 = 384.1 square feet, or 7 double rolls.

Pattern Repeat and Roll Size Reference

These are the allowances this calculator uses, along with the common roll sizes you will see on labels. Always check the actual coverage printed on the roll, since some papers differ.

Pattern repeat or roll type Typical description Allowance or coverage used
No repeat or random match Plain, textured, grasscloth, stripes 10% extra
Small repeat Up to 6 in 15% extra
Medium repeat 7 to 18 in 20% extra
Large repeat Over 18 in 25% extra
American double roll About 27 in wide, sold in pairs 56 sq ft
American single roll Priced per single, often packaged as doubles 28 sq ft
European roll About 20.5 in wide by 33 ft long 57 sq ft

Tips and Common Mistakes

  • Check single versus double pricing. Many American papers are priced per single roll but sold only in double rolls. Make sure the roll size you choose in the calculator matches how the paper is packaged.
  • Buy from one batch. Rolls from different print runs can vary in color. Check that every roll has the same batch or lot number, and buy an extra roll if you think you might need it later.
  • Measure tall walls carefully. On walls taller than about 9 feet, you get fewer full strips per roll, and the real waste can be higher than the allowance. Round up generously.
  • Do not subtract small openings. Outlets, switches and small vents are papered over and trimmed out, so do not deduct them.
  • Prepare the walls first. Wallpaper shows every bump and patch. Fill holes, sand smooth and prime with a wallpaper primer if the paper or the manufacturer calls for it.
  • Peel and stick can behave differently. Removable papers often come in narrower or shorter rolls. Enter the coverage from the label by choosing the closest roll size, or calculate the paper needed and divide by the actual roll coverage.
  • Renters should check the lease. Even removable papers can pull paint on some walls, so test a small area first.

Frequently Asked Questions

How many rolls of wallpaper do I need for an accent wall?
A 12 foot wide wall that is 8 feet high with one window needs about 93 square feet of paper with a small pattern repeat. That works out to 2 double rolls. A wall with no openings and a larger repeat may still need only 2 or 3 rolls.

What is a pattern repeat?
The repeat is the vertical distance before the pattern starts over. Each strip must line up with the one next to it, so larger repeats leave more paper trimmed off the top or bottom of each strip.

What is the difference between a single roll and a double roll?
A double roll is simply twice the length of a single roll on one tube. Double rolls leave fewer short leftover pieces, which is why most American wallpaper is sold that way.

Should I buy an extra roll?
Many people do, especially for large repeats or rooms with lots of corners. A spare roll from the same batch is useful for repairs, and matching it later can be difficult.

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