How many rolls of wallpaper do I need?
Count usable drops, do not divide square footage.
Count how many drops each roll yields (roll length divided by wall height plus 4 in) and how many you need (perimeter divided by roll width). With 8 ft walls, a standard European roll gives only 3 drops.
Why area does not work
A standard 0.53 x 10.05 m roll holds 5.33 m² (57 sq ft). Divide your wall area by that and a 384 sq ft room needs 6.7 rolls, so you buy 7. You would be three short.
The reason is that wallpaper is cut into vertical drops the height of the wall, and whatever is left at the end of the roll is scrap. With 8 ft walls, each drop needs 2.54 m including trim, and a 10.05 m roll yields only three whole drops: 7.6 m used and 2.4 m wasted, a 24 % loss that cannot be avoided.
The correct method
- Add up the perimeter of the walls you are papering.
- Divide the perimeter by the roll width: that is how many drops you need.
- Divide the roll length by (wall height + trim): drops per roll, rounded down.
- Divide drops needed by drops per roll and round up.
Drops per roll by wall height
Swipe to see the whole table
| Wall height | Drop needed | Drops per 10.05 m roll |
|---|---|---|
| 7 ft 3 in | 2.31 m | 4 |
| 7 ft 10 in | 2.49 m | 4 |
| 8 ft 2 in | 2.59 m | 3 |
| 9 ft | 2.84 m | 3 |
| 10 ft 6 in | 3.30 m | 3 |
Pattern repeat
If the paper has a design that must match between drops, each drop needs up to one full repeat of extra length. With a 64 cm repeat, an 8 ft wall needs drops of up to 3.14 m, and a roll yields only 3, or even 2. That can add 30 % to the paper needed.
Why doors and windows are not deducted
The pieces left above a door or below a window are short and carry the pattern at a specific position: they almost never fit elsewhere on the wall. Deducting them is the quickest way to run out of paper.
Sources and methodology
The drop-based method is what manufacturers use in their own coverage tables. The 4 in allowance per drop covers top and bottom trim; with matching patterns, that allowance is replaced by the repeat.
Frequently asked questions
How many rolls of wallpaper for a 12x12 room?
With 8 ft walls and plain paper, about 10 standard European rolls. With 7 ft 6 in walls it drops to 8, because each roll yields four drops instead of three.
How much does one roll of wallpaper cover?
A 0.53 x 10.05 m roll holds 57 sq ft in theory, but with 8 ft walls you only use about 44 sq ft: the rest is lost at the final cut.
Are doors and windows subtracted?
Better not. Offcuts from those areas are rarely reusable, so deducting them leaves you short.
How much extra wallpaper should I buy?
10 % on top of the drops needed, plus one spare roll from the same batch for future repairs.