Work out how many rolls of wallpaper you need for a room.
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How do you calculate how many rolls of wallpaper you need?
Drops per roll = roll length ÷ (wall height + repeat); Strips needed = wall width ÷ roll width; Rolls = strips (plus waste) ÷ drops per roll, rounded up. Each drop is one floor-to-ceiling strip, and a pattern repeat adds length so the design lines up. A 12 m run, 2.4 m high, with 10.05 m × 0.53 m rolls and 10% waste needs about 7 rolls.
Understanding your result
Each “drop” is one floor-to-ceiling strip. A pattern repeat adds length to every drop so the design lines up. Always buy whole rolls from the same batch for a consistent colour.
Formula and method
Drops per roll = roll length ÷ (wall height + repeat). Strips needed = wall width ÷ roll width. Rolls = strips (plus waste) ÷ drops per roll, rounded up.
Worked example
A 12 m wall run, 2.4 m high, with 10.05 m × 0.53 m rolls and 10% waste needs about 7 rolls.
How to use this tool
- Choose metres or feet and enter the total wall width and height.
- Enter the roll length, roll width and any pattern repeat.
- Set a waste allowance, then press Calculate.
About the Wallpaper Calculator
The Wallpaper Calculator works out how many rolls you need to cover a room, allowing for the pattern repeat and a waste margin.
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Frequently asked questions
Should I buy an extra roll?
Yes — keeping a spare roll from the same batch is wise for repairs later, since dye lots vary between batches.