HesapHanem

Wallpaper Calculator

Enter the wall dimensions and your roll size to get the number of rolls to buy.

How it is calculated

The tool works wall by wall, in metres. Each strip is cut to the wall height plus 10 cm of trim: strip = H + 0.10. Strips per roll are floor(roll length ÷ strip), and at least 1. The number of strips across the wall is ceil(wall width ÷ roll width). Rolls to buy are ceil(strips ÷ strips per roll). The wall area W × H is shown for reference but does not drive the count. If one strip (height plus 10 cm) is longer than the roll, no strip can be cut from it and the tool shows no result; zero or negative sizes give none either. Door and window openings are not subtracted, and no pattern repeat is added, so patterned paper may need extra. For several walls, run each wall separately or add their widths if they share the same height.

Worked example

A wall 4.2 m wide and 2.6 m high, with a roll 10.05 m long and 0.53 m wide. Each strip is 2.6 + 0.10 = 2.70 m. One roll gives floor(10.05 ÷ 2.70) = 3 strips (3.72 rounded down). The wall needs ceil(4.2 ÷ 0.53) = ceil(7.92) = 8 strips. Rolls: ceil(8 ÷ 3) = 3. The wall area is 4.2 × 2.6 = 10.92 m², and 3 rolls leave one spare strip's worth of paper.

Try this example →

Common mistakes

  • Dividing wall area by roll area. Strips are cut full height, so the leftover piece at the end of each roll is wasted, and the area method can give too few rolls.
  • Entering the roll width in centimetres (53) or the length in feet. Both must be in metres, and 53 would make the whole wall one strip.
  • Entering a roll shorter than the wall. A roll must be at least the wall height plus 10 cm long (2.70 m for a 2.6 m wall), otherwise the tool shows no result.
  • Buying exactly the result for a patterned paper. The tool adds only 10 cm of trim, so ask the supplier for the repeat length and allow more. Doors and windows are not deducted either.
  • Adding up the widths of all walls into one wide wall of the same height. That is fine, but with different heights each wall must be calculated alone.

About this calculator

Estimating wallpaper needs starts with the wall's area, but the real number of rolls depends on how the roll's dimensions divide into usable strips: a standard roll is cut into vertical strips the height of the wall, and each strip needs a trim allowance — commonly around 10 cm — to account for pattern matching and cutting waste at the ceiling and floor edges. Dividing the wall's width by the strip's usable width gives the number of strips needed, and dividing the roll's length by the trimmed strip height gives strips per roll.

Decorators, DIY renovators and paint-and-paper retailers use this kind of calculation to avoid the two common failure modes of a wallpapering job: running out of rolls partway through a wall, which risks buying a later batch with a slightly different dye lot, or over-ordering and paying for rolls that end up as waste. Getting the roll count right before the project starts is standard practice on any quote or shopping list for a wallpapering job.

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