Quick answer: Work out how many full-height strips you need (wall perimeter ÷ roll width) and how many strips you can cut from one roll (roll length ÷ (wall height + pattern repeat), rounded down). Divide the first by the second and round up. A 12 × 12 ft room with 8 ft walls needs about 7 standard rolls, plus one spare.
Many people estimate wallpaper by dividing the wall area by the area of a roll. That almost always comes up short, because the leftover piece at the end of each roll is usually too short to use. Professional decorators count strips instead.
Step 1: Measure the Perimeter and Height
Add the widths of all the walls you are papering. Subtract about 3 ft (0.9 m) for each door. Do not subtract windows; you still need short pieces above and below them, which usually come from full strips. Measure the wall height from skirting to ceiling.
Step 2: Find the Strip Length
Strip length = Wall height + Pattern repeat
The pattern repeat is printed on the roll label. It is the vertical distance before the design repeats. Plain and random-match papers have no repeat.
Step 3: Strips per Roll
Strips per roll = Roll length ÷ Strip length (round down)
Step 4: Strips Needed and Rolls
Strips needed = Perimeter ÷ Roll width (round up)
Rolls = Strips needed ÷ Strips per roll (round up)
Worked Example
- Room: 12 × 12 ft with 8 ft walls and one door. Perimeter: 48 − 3 = 45 ft
- Roll: 20.5 in × 33 ft, no repeat
- Strips needed: 540 in ÷ 20.5 in = 26.3, so 27 strips
- Strips per roll: 33 ÷ 8 = 4.1, so 4 strips
- Rolls: 27 ÷ 4 = 6.75, so 7 rolls (8 with a spare)
Skip the math: choose your roll size, enter the room and the pattern repeat, and get the number of rolls. Open the free Wallpaper Calculator →
How Pattern Repeat Changes the Count
Full strips per standard 10.05 m (33 ft) roll at different wall heights and pattern repeats:
| Wall height | No repeat | 27 cm repeat | 53 cm repeat | 64 cm repeat |
|---|---|---|---|---|
| 2.4 m (7.9 ft) | 4 | 3 | 3 | 3 |
| 2.5 m (8.2 ft) | 4 | 3 | 3 | 3 |
| 2.7 m (8.9 ft) | 3 | 3 | 3 | 3 |
| 3.0 m (9.8 ft) | 3 | 3 | 2 | 2 |
Going from four strips per roll to three means you need a third more rolls. Large repeats on tall walls make the biggest difference, so always check the label before ordering.
Roll Sizes
- European standard: 0.53 × 10.05 m (about 5.3 m²).
- US double roll: about 20.5 in × 33 ft (56 sq ft).
- US single roll: about 20.5 in × 16.5 ft. Many US papers are priced per single roll but sold in double rolls.
- Wide rolls: 0.70 m or 1.06 m wide; these cover more wall with fewer seams.
Tips
- Check every roll has the same batch number.
- Buy one extra roll for mistakes and repairs.
- Paste-the-wall papers are easier for beginners.
- Painting the other walls? See how much paint you need.
Frequently Asked Questions
How many rolls of wallpaper for a feature wall?
A 4 m wide, 2.5 m high wall needs 8 strips of 0.53 m. A 10.05 m roll gives 4 strips with no repeat, so 2 rolls, or 3 with a spare.
Do I subtract windows when calculating wallpaper?
Usually not. You still need pieces above and below windows. Doors, which run almost floor to ceiling, are normally subtracted.
What does pattern repeat mean?
It is the vertical distance before the pattern repeats. You add it to the wall height when cutting strips so the pattern lines up across seams.
Related Guides
- How to Measure a Room for Flooring (Step-by-Step)
- How Many Tiles Do I Need for a Bathroom Floor or Shower?
- How Much Paint Do I Need for a Room? (Chart by Room Size)
Try the free Wallpaper Calculator or browse all home improvement calculators.