Wallpaper calculator
Walls, roll and repeat in, strips and rolls out.
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This tool runs entirely in your browser. What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.
Example
Example: a 14 × 12 ft bedroom with 8 ft walls, papered with US double rolls
A bedroom 14 × 12 ft with 8 ft walls, one door and two windows, papered with a standard US double roll, 20.5 in wide and 33 ft long, with a 21 in pattern repeat. The calculator counts strips the way a decorator cuts them.
- Perimeter: 2 × (14 + 12) = 52 ft. Taken off: 3 ft for the door and 2 ft for each window, 7 ft, leaving 45 ft of wall.
- 45 ft ÷ 20.5 in = 26.3, so 27 strips.
- Each strip is 8 ft plus 4 in for trimming, 8.33 ft, rounded up to whole repeats: 5 × 21 in = 8.75 ft.
- A 33 ft roll gives 3 strips of 8.75 ft (3.77, rounded down), so 27 ÷ 3 = 9 rolls.
| Roll and walls | Strip length | Strips a roll | Rolls |
|---|---|---|---|
| Double roll 20.5 in × 33 ft, 8 ft walls, no repeat | 8.33 ft | 3 | 9 |
| The same, 21 in repeat | 8.75 ft | 3 | 9 |
| The same roll, 9 ft walls, 21 in repeat | 10.5 ft | 3 | 9 |
| Single roll 20.5 in × 16.5 ft, 8 ft walls | 8.33 ft | 1 | 27 |
| Roll 27 in × 27 ft, 8 ft walls | 8.33 ft | 3 | 7 (20 strips) |
9 double rolls, with or without the repeat: at 8 ft a double roll gives 3 strips either way. Bought as single rolls of 16.5 ft, the same room takes 27, because each gives only one 8 ft 4 in strip. Add one more roll from the same batch.
How it works
- Type the room’s length, width and wall height, and how many doors and windows.
- Type the roll width, length and pattern repeat from the label; leave them empty for a standard roll.
- You get the strip length, the strips a roll gives, the strips the walls need and the rolls to buy.
Frequently asked questions
- How is wallpaper calculated?
- By strips: each strip is the wall height plus trimming, rounded up to whole pattern repeats. A roll gives as many whole strips as fit its length; the walls need their width divided by the roll width. Rolls = strips needed ÷ strips a roll, rounded up.
- What is the pattern repeat?
- The distance before the pattern repeats down the roll, printed on the label. Strips must line up, so each strip uses whole repeats and a larger repeat means more waste.
- Should I buy an extra roll?
- Yes — one more from the same batch number, since another batch may differ slightly in colour.
- Is the result exact?
- It is an estimate from standard figures. Walls are rarely perfectly square and surfaces absorb differently, so buy a little extra from the same batch, and check the figures on the product you choose.
- Single rolls or double rolls?
- Type the length of the roll you will actually buy. Wallpaper in the US is often priced by the single roll but sold as double rolls of about 33 ft, and it matters: with 8 ft walls a 33 ft roll gives 3 strips while a 16.5 ft roll gives only 1, so the same room needs 9 double rolls but 27 single ones.
- Is anything uploaded?
- No. It is worked out in your browser, and nothing you type leaves your computer.