How to use this calculator
- Enter or choose total width of walls to paper.
- Enter or choose wall height.
- Enter or choose width of full-height openings to skip.
- Enter or choose roll width.
- Enter or choose roll length.
- The rolls to buy updates as you type. Use Copy result or Share to keep it.
Method
Drop = Height + Repeat + Trim; Drops per roll = ⌊Roll length ÷ Drop⌋; Drops = ⌈(Wall width − Openings) ÷ Roll width⌉; Rolls = ⌈Drops ÷ Drops per roll⌉ + spares
- Repeat
- vertical pattern repeat
- Trim
- allowance for trimming top and bottom
Worked example
- Drop = 2.4 + 0 + 0.1 = 2.5 m, so ⌊10.05 ÷ 2.5⌋ = 4 drops per roll.
- Drops = ⌈14 ÷ 0.53⌉ = 27.
- Rolls = ⌈27 ÷ 4⌉ = 7.
Walls 14 m round and 2.4 m high need 7 rolls of 0.53 × 10.05 m plain wallpaper.
What the result means
Buy all rolls from the same batch number so the shade matches, and keep a spare in case of damage.
Assumptions and limits
- Adding a full repeat to each drop is a safe allowance for pattern matching.
- Offset (drop) patterns can waste more; ceilings and sloping walls are not handled.
Questions
Why subtract only full-height openings?
Above and below ordinary windows you still need drops, so their width usually saves little paper.
What is a pattern repeat?
The vertical distance before the pattern repeats. Each drop must start at the same point in the pattern, which wastes up to one repeat per drop.
Please note: Quantities are estimates. Confirm requirements with your engineer or supplier before ordering materials.