How many rolls do I need?
Measuring, pattern repeat, and why dividing areas gets it wrong.
Measure the walls
Measure each wall separately — width and height, wall by wall, in feet. Do not measure the room's perimeter as one number: paper is hung in vertical strips, and each wall starts a new one.
Measure the height from the top of the skirting board to the ceiling, at the tallest point. Floors and ceilings are rarely parallel, and the paper has to cover the worst case.
Why area division fails
The obvious method — wall area divided by roll area — is wrong for any patterned paper, and it is wrong in the direction that leaves you short.
Two things break it:
- Every strip starts at a full pattern repeat. If the repeat is 64 cm and your wall is 250 cm tall, each strip consumes 256 cm of paper, not 250. Four repeats, with the offcut wasted.
- An offset pattern shifts every second strip. With a half-drop match, alternate strips start half a repeat further down the roll, so they need that extra length too.
On a typical room the difference between the two methods is one to three rolls. Running out mid-wall is worse than it sounds, because the replacement roll will likely come from a different print batch and the colour will not match exactly.
Use the calculator on the product page. It counts physical strips, rounds each up to whole repeats, accounts for offset patterns, subtracts full-height doorways, and adds 10% for trimming.
What a roll covers
The European standard roll is 53 cm wide and 10.05 m long — about 57 square feet. It is sold as a double roll, which is one physical roll of that size, not two. American papers are often quoted as single rolls of roughly half that, which is where a lot of confusion comes from when comparing prices.
A 53 cm strip is a little under 21 inches. On a 12-foot wall that is seven strips, with the last one cut down.
Doors and windows
A door removes whole strips, so it genuinely reduces the count. A window usually does not: you still need paper above and below it, and the offcuts rarely match anywhere else. Our calculator treats them that way — it subtracts a full-height opening and ignores a window.
Order it all at once
Wallpaper is printed in batches, and colour varies slightly between them. Rolls bought together come from one batch; rolls bought a week later may not. Order the whole job in one go, and one spare roll if the pattern is large — a large repeat wastes more, and a mistake costs a full drop.