Wallpaper Calculator

How to use the wallpaper calculator

1. Choose Metric (m, cm) or Imperial (ft, in).
2. Under Walls, choose Room length + width (all four walls) for a whole room, or Total width of the walls for a feature wall or a few walls (add their widths). Enter the Wall height from the skirting board to the ceiling.
3. Optionally enter a Width to deduct (wide openings), such as a patio door. Leave it at 0 for a safe estimate.
4. Under Roll, pick a Roll size: European standard 0.53 × 10.05 m, European wide 0.70 × 10.05 m, extra-wide non-woven 1.06 × 10.05 m, or US double rolls of 20.5 in × 33 ft or 27 in × 27 ft. Choose Custom size or type over the Roll width and Roll length for any other roll.
5. Under Pattern, choose the Pattern match, enter the Pattern repeat printed on the label, and check the Trim allowance per strip.
6. Read the Length of one strip, the Strips needed, the Strips per roll and the Rolls to buy. The calculation steps are listed below. Reset defaults restores the starting values.

The calculation runs entirely in your browser.

How the number of rolls is calculated

Wallpaper is hung in vertical strips (drops), so the tool counts strips, not square metres:

1. Strips needed = wall width ÷ roll width, rounded up. For a room, the wall width is the perimeter, 2 × (length + width).
2. Strip length = wall height + trim allowance, rounded up to a whole number of pattern repeats for a straight match. For an offset (half-drop) match, half a repeat is added, because every other strip starts half a repeat lower.
3. Strips per roll = roll length ÷ strip length, rounded down: an offcut shorter than the wall is waste.
4. Rolls = strips needed ÷ strips per roll, rounded up.

Example: a 4 × 3.5 m room with 2.5 m walls has 15 m of wall. With 0.53 m wide rolls you need 15 ÷ 0.53 = 28.3, so 29 strips. Each strip is 2.5 m + 10 cm trim = 2.6 m, rounded up to five 53 cm repeats = 2.65 m. A 10.05 m roll gives 3 strips (3.79 rounded down), so you need 29 ÷ 3 = 9.67, that is 10 rolls. In imperial units, a 13 × 11 ft room with 8 ft walls, 20.5 in × 33 ft double rolls and a 21 in repeat also needs 29 strips of 105 in, 3 per roll, so 10 double rolls.

The repeat matters most when it pushes a strip past a threshold. With an offset match and a 64 cm repeat, each strip in the same room becomes 3.2 m + 32 cm = 3.52 m, only 2 strips fit on a roll, and you need 15 rolls instead of 10.

Roll sizes and pattern matches

• European rolls are 53 cm (about 21 in) wide and 10.05 m (33 ft) long, about 5.3 m² per roll. Wider 70 cm and 1.06 m non-woven rolls cover more wall with fewer seams.
• US rolls are priced per single roll but sold as double rolls (one continuous piece of two single rolls), commonly 20.5 in × 33 ft or 27 in × 27 ft, about 56 sq ft each. Always enter the size of the piece you actually buy.
• Free match (stripes, textures) has no repeat to align: strips can be cut straight from the roll.
• Straight match: the pattern lines up horizontally at the same height on every strip.
• Offset or half-drop match: the pattern is shifted by half a repeat from one strip to the next, which uses more paper.

Buying tips

• Buy all rolls with the same batch (lot) number; colours vary between print runs. Add one spare roll for mistakes and future repairs.
• Pre-cut and number all strips before you hang them, and check the pattern direction arrow on the roll.
• Buy the paste recommended for the paper (non-woven papers are usually hung with paste applied to the wall).
• The paper manufacturer’s instructions on paste, soaking time and surface preparation prevail over this estimate.