Why wallpaper is counted in strips, not square feet
Dividing wall area by roll area underestimates. Each roll is cut into full-height strips (drops), and whatever is left at the end of a roll is usually too short for another one. So the reliable method counts strips:
- Strips needed: wall width ÷ roll width, rounded up.
- Length of each strip: wall height plus about 4 in (10 cm) for trimming. With a pattern, round up to a whole number of repeats so the pattern lines up.
- Strips per roll: roll length ÷ strip length, rounded down.
- Rolls: strips needed ÷ strips per roll, rounded up.
Worked example: a 12 × 12 ft room with 8 ft walls, US double rolls
The walls run 48 ft (576 in). Rolls are 20.5 in wide, so you need 29 strips. Each strip is 8 ft plus 4 in, about 100 in. A 33 ft (396 in) roll gives 3 full strips. 29 ÷ 3 = 9.7, so buy 10 rolls.
Roll sizes
| Roll | Size | Coverage |
|---|---|---|
| US double roll | 20.5 in × 33 ft | About 56 sq ft before waste |
| Euro roll | 0.53 × 10.05 m | About 5.3 m² before waste |
| Wide roll | 27 in × 27 ft | About 60 sq ft before waste |
US wallpaper is often priced per single roll but sold only in double rolls. Check which one a price refers to.
Pattern repeat and match
The repeat is the distance before the pattern starts again, printed on the label. Large repeats waste more paper per strip. A straight match lines up across strips at the same height. A drop match shifts every other strip by half a repeat, which can waste a little more than the calculator assumes; one spare roll covers it.
Buy from one batch
Colors vary slightly between print runs. Check that every roll has the same batch or dye lot number, and buy a spare roll now rather than hoping to match it later.