Wallpaper Calculator: How Many Rolls Do I Need?
Enter the distance around the room, the wall height and the pattern repeat. This counts strips rather than dividing areas — because wallpaper hangs in full-height pieces and a pattern repeat wastes part of every one, which an area calculation quietly ignores.
Room and paper
Measure around the walls you are papering, and floor to ceiling at the tallest point.
Roll dimensions vary between products and between markets — check yours and change the figures. Buy all your rolls from one batch: wallpaper colour shifts between print runs, and a replacement roll will rarely match.
How many rolls of wallpaper do I need?
Wallpaper hangs in full-height strips, so the question is how many strips go around the room and how many strips a roll yields. Both are whole numbers, and both round in ways that dividing areas cannot capture.
Notice what happens with 9 ft walls: the same roll now yields only three strips instead of four, so the same room needs 8 rolls rather than 6. A foot of extra height costs a third more paper — nothing about the area calculation would tell you that.
Why a pattern repeat costs so much
Every strip after the first has to start at the right point in the pattern, so up to one full repeat is trimmed off each one. A 21 inch repeat on an 8 ft wall costs about as much as making the wall a foot taller.
| Repeat | Typical of |
|---|---|
| None | Plain, textured or random-match paper |
| 12 in | A small pattern |
| 21 in | A large pattern |
The result shows how much of what you buy ends up as offcut, so the cost of a large pattern is visible before you commit to it.
Doors and windows
A doorway removes a full floor-to-ceiling strip, so it is deducted as a strip rather than as an area. Windows are not deducted at all: the paper above and below a window still has to come off a full-height strip, and the offcut is rarely usable.
This is deliberately conservative. Running out of a discontinued paper two strips from the end is a much worse outcome than having one spare roll.
How to measure
Add up all the walls you are papering. If you are only doing one feature wall, use that wall’s width.
Strips are cut to the tallest run; an uneven ceiling costs you the difference.
It is usually printed as the pattern or vertical repeat, in inches or centimetres.
Common mistakes
- Dividing wall area by roll area, which under-orders any patterned paper.
- Ignoring the repeat, then finding a roll yields one fewer strip than expected.
- Deducting windows and coming up short.
- Buying rolls from different batches, so the colour does not match.
Painting the rest of the room?
Work out the ceiling and any walls that are not being papered.
Open the Paint Calculator →