Wallpaper is not sold by area, it is used in drops — and only whole drops come off a roll. That makes the answer jump in steps rather than scale smoothly, and it is why a large pattern repeat can cost you an entire drop per roll without changing the area at all.
Enter the walls, then the roll and the pattern repeat off the label. Deduct openings only if they are large.
Works in metric and US imperial — you choose at the start and can switch at any time. Every figure this calculator uses is published with its source, and the result comes with a printable order sheet. No account, no email, and nothing you type leaves your browser.
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And only whole drops come off a roll. That makes the answer jump in steps rather than scale smoothly, and it is why a large pattern repeat costs noticeably more paper than a plain one for exactly the same wall: every drop has to be cut to align with the last, and the offcut is usually too short to use. Enter the roll length and the pattern repeat from the label rather than estimating them.
Ceilings are rarely level and floors rarely flat. Use the tallest measurement plus trim for every drop, or you will be short at one end of the room. Trim allowance is per drop, top and bottom — 100 mm total, 50 mm each end, is normal. Less is possible in a very square room with a steady hand; more if the ceiling line wanders.
Batch numbers matter more here than almost anywhere: print runs differ in shade enough to see across a seam, so check every roll before you start rather than after hanging three. Start in the least visible corner rather than at the door — the pattern will not match where the last drop meets the first, which is unavoidable in any room, so put that mismatch somewhere nobody looks. And note that paste-the-wall and paste-the-paper are different products with different soaking times; paste-the-paper needs every drop soaked for the stated time, and for the same time, or the drops expand by different amounts.
Work in drops rather than area: how many full-height drops the wall needs, and how many drops come off one roll. Only whole drops are usable, so the answer steps up rather than scaling smoothly with wall size.
Because every drop has to be cut so the pattern aligns with the one beside it, and the offcut from matching is usually too short to use elsewhere. A large repeat can add significantly to the roll count for the same wall area.
In the least visible corner. The pattern cannot match where the last drop meets the first — that is unavoidable in any room — so the mismatch should land somewhere nobody looks, not beside the door.
About 100 mm in total, 50 mm at each end. Measure the wall height in several places and use the tallest figure, because ceilings are rarely level and floors rarely flat.