Wallpaper Calculator
Count the rolls of wallpaper your room needs, with the pattern repeat taken into account.
Last reviewed 2026-06-06
Wallpaper is deceptively easy to get wrong: the pattern repeat means you cannot simply divide wall area by roll area. The honest method counts full “drops” (floor-to-ceiling strips) and how many fit per roll.
Enter your wall perimeter and height, the roll dimensions from the label, and the pattern repeat. We calculate the number of drops, how many come from each roll, and the total rolls to buy.
How to use the Wallpaper Calculator
- Measure the total length of the walls (the perimeter) and the wall height.
- Enter the roll length and width from the wallpaper label.
- Enter the pattern repeat (use 0 for plain paper).
- Read the number of rolls — and always buy one spare.
Frequently asked questions
How many rolls of wallpaper do I need?
Count vertical “drops”: divide the wall perimeter by the roll width to get the number of drops, then divide the roll length by the drop length (wall height plus pattern repeat) to see how many drops each roll yields. Rolls = drops ÷ drops-per-roll, rounded up.
Why does the pattern repeat matter?
To line the pattern up between strips you waste up to one repeat length per drop. A large repeat can mean you get one fewer usable drop per roll, pushing up the roll count — which is why area-based estimates fall short.
Should I buy extra wallpaper?
Yes — always buy at least one extra roll, and keep it. Wallpaper is printed in batches and later rolls can differ slightly in colour, so a matching spare is invaluable for repairs.
What is a standard wallpaper roll size?
A common European roll is about 10 m long and 53 cm wide; many US rolls are sold as “double rolls”. Always use the figures printed on your specific roll, as sizes vary by brand.