🧻Wallpaper Calculator

About this tool

Enter the total width of the walls you are papering, or type the room's length and width and press the button to use its perimeter. Then enter the wall height, the roll width and length, the pattern repeat, the width of doors and a trim allowance. The calculator shows the rolls to buy, the number of drops, how many drops each roll gives, the cut length and the waste per roll. Metric and imperial units are both supported.

How wallpaper is measured

Decorators count wallpaper in drops, the full-height strips hung side by side, not in square metres. Each drop is the wall height rounded up to a whole number of pattern repeats, plus about 10 cm (4 in) for trimming top and bottom. A roll yields only as many whole drops as fit its length, and the offcut is waste, which is why area-based estimates often fall short. Take a room 4 × 3.5 m with 2.4 m walls, papered all round, using standard 0.53 × 10.05 m rolls with a 53 cm pattern repeat. Each drop is cut at 2.75 m, so a roll gives three drops. The 15 m perimeter needs 29 drops, less one saved by the door, so 28 drops means 10 rolls. The same paper with no pattern to match gives four drops a roll and needs only 7 rolls. Windows are deliberately left in, because the short pieces above and below rarely save a whole roll. Honest limits: check that every roll carries the same batch number, since shades vary between batches, and keep a spare roll for repairs. The paint calculator handles ceilings and woodwork, the area calculator measures awkward walls and the unit converter switches between feet and metres.

Frequently asked questions