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Wallpaper Calculator
Find how many rolls of wallpaper a room needs from the wall widths, height, roll size, and pattern repeat, with whole strips saved for doors and windows.
Wallpaper Calculator: Wallpaper is hung in strips the height of the wall, so the calculation counts strips rather than area. Each strip is the height plus a trimming allowance, rounded up to whole pattern repeats; the number of strips a roll gives is the roll length divided by that, rounded down; and the strips needed are the wall width divided by the roll width, rounded up. Rolls are the strips divided by strips per roll, rounded up. Runs 100% locally in your browser with zero server file uploads.
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- Home & family tools
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Each strip is the wall height plus 10 cm (4 in) for trimming, rounded up to whole pattern repeats so the pattern lines up; an offset match needs half a repeat more on average. Only whole strips are saved by a door or window, because the pieces above and below still need paper. Roll sizes vary, so copy them from the label.
A worked example
A room with walls of 4, 3.5, 4, and 3.5 m is 15 m around. With 53 cm rolls, that is 15 ÷ 0.53 = 28.3, so 29 strips. At 2.5 m high plus 10 cm trim, a 10.05 m roll gives 3 strips of 2.6 m, so 29 strips need 10 rolls; a 1.2 m window saves 2 strips and brings it to 9.
For the floor of the same room, see the square footage calculator.
Roll sizes
Standard European rolls are 53 cm wide and 10.05 m long; wide rolls of 70 cm or 1 m also exist. In the US, rolls are often sold as double rolls of about 20.5 in by 33 ft. Patterned papers print the repeat on the label.
How to use it
- Choose metric or imperial, then enter each wall's width and the height to paper.
- Enter the roll width and length from the label, and the pattern repeat if there is one.
- Add the widths of doors and windows, and read the rolls and strips needed.
Privacy & limitations
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Frequently asked questions
Why buy an extra roll?
Rolls are printed in batches whose colour can differ slightly, so buying a spare from the same batch saves trouble if you make a mistake or need a repair later.
What is an offset or drop match?
The pattern lines up half a repeat lower on each neighbouring strip, which wastes about half a repeat more per strip than a straight match.
Why does the door save so little?
Only whole strips are saved: the paper above a door and above and below a window still needs strips, cut from the same rolls.
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