Wallpaper calculator: how many rolls of wallpaper do I need?
Measure the room and the wall height, and enter the pattern repeat from the label. You get the strips you need and how many double rolls to buy. A standard US double roll is 20.5 inches wide and 33 feet long.
- Pattern repeat
- Counted by strips
- Your roll size
Only skip openings that run floor to ceiling, like a wide doorway. You still need paper above doors and around windows, so don't subtract those.
Before you wallpaper
How it works
Strips = total wall width × 12 ÷ roll width in inches, rounded up. Wall width is 2 × (length + width), minus any full-height openings.
Strip length = wall height + pattern repeat, so each strip can be shifted to line up the pattern.
Strips per roll = roll length ÷ strip length, rounded down. Rolls = strips ÷ strips per roll, rounded up. This is the strip method Bob Vila describes, and it doesn't subtract doors and windows.
Roll size defaults to a US double roll of 20.5 inches by 33 feet (about 56 square feet), like Brewster's standard rolls. European rolls are smaller, so enter yours.
About this tool
Who it's for
For anyone papering a room or an accent wall.
Example
You enterA 12x12 room, 8-foot walls, a 21-inch repeat
You get29 strips, 3 per roll, so 10 double rolls.
What's different
- Counts strips like an installer, not just square feet.
- Adds the pattern repeat to every strip.
- Works with any roll size.
Gotchas and tips
- Large repeats waste a lot. A 24-inch repeat can cut strips per roll by a third.
- Buy one extra roll from the same batch.
- Check every roll for the same batch number.
Privacy: Runs entirely in your browser. Nothing you type is sent to us, and anything it remembers is saved on this device only.
Built and maintained by the GrabTheHammer team, using published figures from manufacturers and agencies, listed below. Updated November 2026. Spot a problem? Tell us.
Wallpaper questions
How many rolls of wallpaper for a 12x12 room?
With 8-foot walls and no pattern repeat, you need 29 strips. A 33-foot double roll gives 4 strips, so buy 8 double rolls, plus one spare.
What is a double roll?
Most US wallpaper is sold as double rolls, about 20.5 inches wide and 33 feet long, or about 56 square feet. Some stores list the price per single roll, so check which one a price means.
Should I subtract doors and windows?
Usually not. You still need paper above doors and around windows, and the scraps rarely match the pattern. Only skip wide floor-to-ceiling openings.
Sources: Bob Vila: how to measure for wallpaper; Brewster double roll size (20.5 in x 33 ft); Selected Wallpapers: European vs. double rolls.