Calculators

Wallpaper Calculator

Rolls of wallpaper for a room or feature wall, counted strip by strip and allowing for the pattern repeat.

How it works

Wallpaper is hung in full-height strips, so count strips rather than square feet. The strips needed are the wall width divided by the roll width, rounded up. Each strip is cut to the wall height plus about 4 in for trimming, and then up to a whole pattern repeat so the next strip lines up. Divide the roll length by that cut length and round down to get the strips each roll yields; the leftover is waste.

rolls = ⌈strips ÷ ⌊roll length ÷ cut length⌋⌉
Cut length
Wall height + 4 in, rounded up to the pattern repeat
Pattern repeat
The distance before the design repeats, on the label
Roll
A US double roll or a European roll: about 20½ in × 33 ft

Worked example

A 12 × 14 ft room with 8 ft walls and one door, papered with 20½ in × 33 ft rolls with a 21 in repeat.

  1. 1Walls: 2 × (12 + 14) = 52 ft, less a 3 ft door = 49 ft
  2. 2Strips: 49 × 12 ÷ 20.5 = 28.7, so 29
  3. 3Cut length: 96 + 4 = 100 in, rounded up to 5 × 21 = 105 in
  4. 4Strips per roll: 396 ÷ 105 = 3.8, so 3
  5. 5Rolls: 29 ÷ 3 = 9.7, so 10

10 rolls, $600 at $60 a roll. Each roll leaves an 81 in offcut, too short for another strip.

Frequently asked questions

Why not just divide the wall area by the roll area?

Because every strip is cut to full height and the offcuts are rarely long enough to use. A 33 ft roll gives three 105 in strips and leaves 81 in over, which is too short for another. Area-based estimates often come up one or two rolls short.

What is a pattern repeat and a drop match?

The repeat is the vertical distance before the design starts again. In a straight match, the pattern lines up straight across adjacent strips. In a drop (offset) match it lines up half a repeat lower, which can waste a little more. Either way, a bigger repeat means more waste per strip.

Should I subtract windows and doors?

Subtract doors and openings that run nearly to the ceiling. Do not subtract windows: you still need strips above and below them, and those short pieces rarely come from offcuts cleanly. Buy one spare roll from the same batch for repairs.

Related calculators

More in Construction & DIY