How it works
Room size, ceiling height, and what you are not papering.
Measure the room
Length and width in feet. We work out the perimeter for you.
Subtract openings
Each door counts as 21 ft² and each window as 15 ft².
Get the roll count
Net area to cover and how many rolls that takes.
Half the roll is not on your wall
A standard double roll holds around 56 square feet of paper. You will get nowhere near that onto the wall. Between trimming the top and bottom of each drop and matching the pattern between drops, the usable figure is closer to 28 square feet — which is the number this calculator works from, and the reason a room that looks like it needs six rolls actually takes eleven.
How much you lose depends on the pattern repeat. A plain or random-match paper wastes very little, and you can push the usable figure up towards 35 ft². A large repeat — anything over about 20 inches — means cutting each drop to align with the last, and the offcuts pile up fast. For those, drop the usable figure to 25 ft² or lower.
Doors and windows are subtracted here at 21 and 15 square feet, the same standard figures the paint calculator uses. Be a little careful with that: you cannot always use the paper saved above a door, because the drop still has to run full height to match the pattern on either side. On a heavily patterned paper, ignore the deductions entirely and paper the full perimeter.
Buy every roll in one go and check the batch number printed on the label. Wallpaper is printed in runs, and the colour shifts between them enough to see on a wall. This is the same trap as tile dye lots, and it ends the same way: a strip that does not match, and no way to buy more of the original.
Frequently asked questions
How many rolls of wallpaper for a 12x12 room?
About 13 rolls for an 8 foot ceiling with one door and one window, at 28 ft² usable per roll.
How much of a roll is actually usable?
Around 28 ft² of a 56 ft² double roll once trimming and pattern matching are accounted for. Large repeats waste more.
Should I subtract doors and windows?
For plain papers, yes. For a large pattern repeat, paper the full perimeter — the drop still has to run full height to match.
Why does the batch number matter?
Colour shifts between print runs. Rolls from different batches can be visibly different on the wall, and you cannot buy more of the original later.
More material calculators
Estimates are for planning only. Confirm quantities with your supplier before ordering.