Strips, repeats & rolls
Wallpaper roll calculator
How many rolls to buy, worked out strip by strip the way a decorator hangs them: strips per wall, the length each strip takes once the pattern lines up, and how many strips one roll gives.
Rolls to buy
10 rolls of 53 cm × 10.05 m rolls, 53 cm repeat, straight match, walls 2.4 m high.
- Rolls to buy1053 cm × 10.05 m rolls
- Strips (drops)303 strips per roll
- Cut each strip2.65 m2.5 m + 15 cm to match the pattern
| Wall | Width | Strips |
|---|---|---|
| Wall A (length) | 4 m | 8 |
| Wall B (width) | 3.5 m | 7 |
| Wall C (length) | 4 m | 8 |
| Wall D (width) | 3.5 m | 7 |
| Total | 15 m | 30 |
| Item | Value |
|---|---|
| Strip length on the wall | 2.4 m + 10 cm trim = 2.5 m |
| Pattern | 53 cm repeat, straight match |
| Roll used per strip | 2.65 m |
| Strips from one roll | 3 (offcut 2.1 m) |
| Wall area (no deductions) | 36 m² (387.5 ft²) |
| Paper bought | 53.27 m² (573.3 ft²) |
Buy every roll from one batch (the batch or lot number is printed on the label), and keep the label. Doors and windows are not deducted: their short strips usually come out of the offcuts.
How to use the wallpaper calculator
Enter the room's length and width, or switch to Wall by wall for a feature wall or a room with alcoves, and the height from the top of the skirting to the ceiling. Doors and windows are not taken off: their short strips above and below usually come out of offcuts, and the margin covers a mistake.
Pick the roll size from the label. The pattern repeat is the distance before the design starts again, and the match says how neighbouring strips line up:
- Free match: plain, textured or striped papers that line up anywhere, so nothing is lost.
- Straight match: the design runs straight across, so each strip is cut to a whole number of repeats.
- Half-drop match: every other strip is shifted down by half a repeat, so each strip is cut to whole repeats plus a half.
The trim allowance is the extra at the top and bottom for trimming to the ceiling and skirting (10 cm or 4 in in all is a common rule of thumb).
Worked example
A 4 × 3.5 m room with 2.4 m walls has walls of 4, 3.5, 4 and 3.5 m. With 53 cm rolls they take 8, 7, 8 and 7 strips: 30 in all. Each strip is 2.4 m plus 10 cm trim, 2.5 m, rounded up to five 53 cm repeats, 2.65 m. A 10.05 m roll gives three such strips, so you need 30 ÷ 3 = 10 rolls.
Roll sizes and batches
Most European wallpaper comes on rolls 10.05 m long and 53 cm wide, about 5.3 m² of paper, which is the size Boråstapeter, a Swedish maker, gives as usual (its own papers can differ, so check the product). In the US, papers are commonly sold by the double roll: York Wallcoverings lists one design at 20.5 in × 33 ft, about 56.4 ft². Wide non-woven papers and murals come in other sizes, so use "Other size" with the figures from the label.
Wallpaper is printed in batches whose shade can differ slightly. Graham & Brown advises that all your rolls come from the same batch, printed on the label, and that you note it, because a later order may be from a different run.
Sources
- Boråstapeter, Wallpaper calculator guide: rolls are usually 10.05 m long and 53 cm wide; pattern repeat types (straight match, half drop).
- York Wallcoverings, Colette wallpaper product page: double roll of 20.5 in × 33 ft covering about 56.4 ft², with its repeat and match.
- Graham & Brown, What is a batch number?: buy every roll from the same batch.
Questions
How many rolls of wallpaper do I need for a 4 × 4 m room?
With 2.4 m walls and 53 cm × 10.05 m rolls, each 4 m wall takes 8 strips, so 32 strips in all. A free-match paper gives 4 strips of 2.5 m per roll (8 rolls); a 53 cm straight-match repeat gives 3 per roll (11 rolls). The repeat makes that much difference.
Where do I find the pattern repeat and match?
On the roll label and on the product page, usually as a symbol and a length in centimetres or inches. If a paper is listed as free match or random match, choose free match here and the repeat is ignored.
Why does a half-drop pattern need more paper?
Each strip has to start half a repeat lower than the one before it, so when strips are cut one after another from the same roll, about half a repeat is lost between them. Some decorators cut from two rolls at once to save part of that.
Should I subtract doors and windows?
Not for rolls. The space over a door or under a window still needs short strips, and these are cut from offcuts. Leaving openings in gives a small margin, which is useful because a later roll may not match the batch.
How much paper is lost to the trim?
Each strip is cut a little longer than the wall so it can be trimmed neatly at the ceiling and skirting. The example allows 10 cm (about 4 in) per strip in all; uneven ceilings may need more.