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Wallpaper Calculator: How Many Rolls Do I Need?

Find how many wallpaper rolls you need from your wall size, roll size and pattern repeat. Handles straight and drop matches, doors and US or European rolls.

How to use the Wallpaper Calculator

  1. Enter the total width of the walls you will cover and the wall height.
  2. Pick your roll size, or enter the width and length from the label.
  3. Enter the pattern repeat from the label, or 0 for a pattern with no repeat, and choose straight or drop match.
  4. Read the strips needed, the strips per roll and the rolls to buy.

How the wallpaper calculator works

Wallpaper is hung in vertical strips, so the calculator counts strips, not square feet.

  1. Strips needed = total wall width (minus full-height doors) divided by the roll width, rounded up.
  2. Cut length = wall height plus a trim allowance, rounded up to a whole number of pattern repeats. A drop match adds half a repeat first.
  3. Strips per roll = roll length divided by the cut length, rounded down to whole strips.
  4. Rolls = strips needed divided by strips per roll, rounded up.

The leftover piece on each roll is usually too short for another full strip, which is why counting strips needs more paper than dividing the wall area by the roll area.

Worked example

A 12 by 12 foot room (48 feet of wall) with 8 foot walls and a 20.5 inch by 33 foot roll with no pattern repeat:

  • Strips needed: 48 ft x 12 / 20.5 in = 28.1, rounded up to 29
  • Cut length with a 4 inch trim allowance: 96 + 4 = 100 in
  • Strips per roll: 396 in / 100 in = 3.96, rounded down to 3
  • Rolls: 29 / 3 = 9.7, rounded up to 10 rolls

The roll has 96 inches left after three strips, almost enough for a fourth. With a 2 inch trim allowance the cut length is 98 inches, four strips fit, and the same room needs 8 rolls. Ask your installer how much trim they need before you decide.

US and European rolls

A US double roll is commonly 20.5 inches wide and 33 feet long, about 56 square feet. A single roll is half the length, about 16.5 feet. European rolls are usually 53 centimeters (about 20.9 inches) wide and 10.05 meters (about 33 feet) long. The labels list the size, and the pattern repeat, so enter those if they differ from the presets.

Pattern repeat and match

With no repeat (a random or texture pattern) there is no matching waste. With a straight match the design lines up straight across, so every strip is cut to a whole number of repeats. With a drop match the pattern steps down half a repeat from strip to strip, which needs extra length. Larger repeats mean more waste, and a repeat close to the strip length can leave very little for the next cut.

Doors, windows and mistakes

Enter the total width of full-height openings such as doors to take them out of the wall width. Windows are left in, because the strips above and below them still need full lengths cut. Buy an extra roll if you can, so that every roll comes from the same batch.

More home project calculators

Painting instead? Our guide on how to paint a room like a pro covers the steps. For floors, use the flooring calculator. For the roof, there is a roofing calculator.

Frequently asked questions

How many rolls of wallpaper do I need?

Divide the total wall width by the roll width to get the number of strips, work out how many strips of your wall height fit on one roll, and divide. The calculator does this and rounds up. A 12 by 12 foot room with 8 foot walls and no pattern repeat needs 29 strips.

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

In the US, wallpaper is priced per single roll but sold as double rolls. A double roll is commonly 20.5 inches wide and 33 feet long, about 56 square feet, so you order in multiples of two single rolls. Check the label, because sizes vary by brand.

What is a pattern repeat?

It is the vertical distance before the design repeats. Each strip has to be cut to a multiple of the repeat so the pattern lines up from strip to strip, so a larger repeat wastes more paper and can mean more rolls.

What is a drop match?

In a drop match, the pattern on each strip is offset by half a repeat from the strip beside it. That needs extra length on each strip, so it usually takes more paper than a straight match. The calculator adds half a repeat for a drop match.

Should I buy an extra roll?

Many sellers advise it, for mistakes and so every roll comes from the same print batch. If a strip is hard to cut from what is left, an extra roll is cheaper than a reorder that may not match.

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