Wallpaper Calculator
Work out how many rolls of wallpaper a room needs from the perimeter, wall height, roll size and pattern repeat.
How many rolls the room needs, pattern repeat included.
How the wallpaper calculator works
Wallpaper is hung in vertical drops. The number of drops is the perimeter divided by the roll width; each drop is the wall height plus the pattern repeat (so patterns can be matched) plus trimming. Drops per roll = roll length ÷ drop length, rounded down; rolls = drops ÷ drops per roll, rounded up. A standard roll is 53 cm × 10.05 m (20.5 in × 33 ft in the US).
Decorators do not subtract doors and windows for wallpaper — the offcuts are rarely usable — so the calculator follows that convention.
Formula: rolls = ⌈(perimeter ÷ roll width) ÷ ⌊roll length ÷ (height + repeat)⌋⌉
Worked examples
| Inputs | Rolls to buy | Note |
|---|---|---|
| 14 m perimeter, 2.4 m walls, plain paper | 7 | 27 drops, 4 per roll → 7 rolls |
| Same room, 53 cm pattern repeat | 9 | only 3 drops per roll → 9 rolls |
| 46 ft perimeter, 8 ft walls, US roll | 9 | 27 drops, 3 per roll → 9 rolls |
FAQFrequently asked questions
Why does the pattern repeat add so much?
Each drop must start at the same point in the pattern, so up to one full repeat is cut off per drop. A 53 cm repeat on a 2.4 m wall turns 4 drops per roll into 3.
Should I subtract doors and windows?
Decorators usually do not — the pieces around openings are cut from full drops. Subtract only very large openings.
How many rolls per batch should I buy?
All of them from one batch number, plus one spare. Batches differ slightly in colour.
What is a double roll?
US papers are often sold as double rolls (about 20.5 in × 33 ft); European rolls are single (53 cm × 10.05 m). Enter the size of the roll you are actually buying.
Where these figures come from
- The Engineering ToolBox — material densities, coverage and unit data — bulk densities, concrete at 2,400 kg/m³, board and sheet sizes
- Cement Concrete & Aggregates Australia — concrete basics and yields — bag yields, density 2,400 kg/m³
- Australian Building Codes Board — the National Construction Code
Last checked: September 2026. Coverage rates and material sizes are typical manufacturer figures — check the product you buy.