How many rolls of wallpaper do I need?

How it works

Tiles and flooring are counted by area. The surface is length × width; add an allowance for cut pieces, breakage and mistakes; then divide by one tile's area, or by the area a pack covers, and round up.

Wallpaper is counted in strips, because a roll is cut into lengths that each run from the ceiling to the floor. The walls need their width divided by the roll width, rounded up, in strips. Each strip is the wall height plus the pattern repeat, and a roll gives as many whole strips as fit its length; the offcut is waste. A standard European roll is 0.53 m wide and 10.05 m long, so 2.5 m walls get 4 strips from a roll.

The extra allowance is a rule of thumb, not a measurement: about 10 % is common for straight laying, and more is wise for diagonal patterns, small rooms with many cuts, or large tiles. Buy everything from the same batch, and keep a few spare pieces for repairs. Windows and doors are not taken off; leave them in, or reduce the wall width yourself.