Wallpaper calculator
Rolls needed for a room, with waste built in for pattern matching — the bigger the repeat, the more gets trimmed away.
Room details
How this is calculated
Wall area starts the same way it does for paint: 2 × (length + width) × height, minus roughly 20 sq ft per door and 15 sq ft per window since wallpaper doesn't go over them. What's different from paint is the waste factor — wallpaper is cut into drops (floor-to-ceiling strips), and each drop has to line up with the pattern on the one next to it. A random or no-repeat pattern wastes very little, around 10%. A small repeat under 12" wastes more like 15%, and a large repeat of 12" or more can waste 25% or more, since a big chunk of each drop gets trimmed just to keep the pattern aligned. That adjusted area is divided by the roll size — most US wallpaper is sold as a "double roll" covering about 56 sq ft — and rounded up to a whole roll.
How many rolls for a 12×12 room?
At 8 ft ceilings with one door and two windows and a large pattern repeat, that room needs about 8 double rolls. A smaller or no-repeat pattern could bring it down to 6–7.
Why does pattern repeat matter so much?
Every drop above the first has to be cut so its pattern lines up with the drop next to it, which means part of each new roll gets thrown away just for alignment. Large, elaborate repeats simply waste more material than small or random patterns.
Should I round up or order exactly what this says?
Round up to the next full roll, and consider buying one extra of the whole order — wallpaper runs age out of production, and getting a mismatched dye lot later for repairs is far more expensive than one spare roll now.
Once you know how much to order
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Peel-and-stick wallpaper, double roll
Covers ~56 sq ft, matches the default above.
View on Home DepotWallpaper cutting knife & guide
For clean seams and trimming at baseboards.
View on Home Depot