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This wallpaper calculator tells you how many rolls of wallpaper you need to paper a room. Unlike simple area calculators, it works out how many full-height strips you can cut from each roll, taking the pattern repeat into account, which is how professional decorators estimate.
How to Use the Wallpaper Calculator
- Enter the room length, width and wall height.
- Enter the number of doors. Each door removes about 3 ft (0.9 m) of wall width.
- Choose the roll size printed on the label. Standard European rolls are 0.53 × 10.05 m; US double rolls are about 20.5 in × 33 ft.
- Enter the pattern repeat from the label. Use 0 for plain or random-match paper.
- Optionally enter the price per roll.
Wallpaper Formula
Strip length = Wall height + Pattern repeat
Strips per roll = Roll length ÷ Strip length (rounded down)
Strips needed = Wall perimeter ÷ Roll width (rounded up)
Rolls = Strips needed ÷ Strips per roll (rounded up)
Offcuts shorter than a full strip are rarely usable, which is why the number of strips per roll is rounded down. This method gives a more realistic answer than dividing the wall area by the roll area.
Worked Example: 12 × 12 ft Room with 8 ft Walls
- Perimeter: 2 × (12 + 12) = 48 ft, minus 3 ft for one door = 45 ft
- Strips needed: 45 ft (540 in) ÷ 20.5 in = 26.3, so 27 strips
- Strips per 33 ft roll: 33 ÷ 8 = 4 full strips
- Rolls: 27 ÷ 4 = 6.75, so 7 rolls, or 8 with a spare
Metric example: a 4 × 3 m room with 2.5 m walls and one door needs 25 strips. A 10.05 m roll gives 4 strips, so you need 7 rolls. With a 64 cm pattern repeat, each strip becomes 3.14 m, only 3 fit on a roll and you need 9 rolls.
Common Wallpaper Roll Sizes
| Roll type | Width | Length | Area |
|---|---|---|---|
| European standard | 0.53 m (20.9 in) | 10.05 m (33 ft) | ≈5.3 m² (57 sq ft) |
| US double roll | 20.5 in (0.52 m) | 33 ft (10.06 m) | ≈56 sq ft (5.2 m²) |
| US single roll | 20.5 in | 16.5 ft | ≈28 sq ft |
| Wide roll | 0.70 m or 27 in | 8.2–10.05 m | ≈5.6–7 m² |
| Extra-wide roll | 1.06 m | 10.05 m | ≈10.6 m² |
Understanding Pattern Repeat
The pattern repeat is the vertical distance before the design repeats. When you hang the next strip, you may have to slide it up or down to line up the pattern, which wastes paper. Large repeats can reduce the number of strips per roll from four to three, which adds several rolls to a room. A straight match lines up across at the same height; a drop match is offset by half the repeat, but the same allowance works for estimating.
Wallpaper Tips
- Check that every roll has the same batch or lot number; colors can vary between print runs.
- Buy one extra roll for mistakes and future repairs.
- Measure each wall separately if the heights differ, for example under stairs or sloped ceilings.
- Painting the other walls? Use our paint calculator.
Frequently Asked Questions
How many rolls of wallpaper do I need for a 12×12 room?
With 8 ft walls, one door and a standard 20.5 in × 33 ft double roll, you need about 7 rolls, or 8 including a spare. A large pattern repeat can increase this.
How do I calculate wallpaper with a pattern repeat?
Add the pattern repeat to the wall height to get the length of each strip. Then work out how many full strips fit on one roll and divide the strips you need by that number.
How many square meters are in a roll of wallpaper?
A standard European roll of 0.53 × 10.05 m covers about 5.3 m², but because offcuts are wasted, the usable area is usually closer to 4.5–5 m².
Should I subtract windows from wallpaper?
Usually not. You still need strips above and below windows, and those pieces often come from full-length strips. Doors are normally subtracted.
Why buy an extra roll of wallpaper?
An extra roll covers cutting mistakes and allows future repairs. Rolls from a later batch may not match the color exactly.
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