Wallpaper Calculator
This wallpaper calculator tells you how many rolls a room needs. Enter the room size and wall height, note the doors and windows, set your roll coverage and a waste margin for pattern matching, and you'll get the rolls to buy. Everything updates as you type, so it's easy to plan a feature wall or a whole room. It's free and runs in your browser, so pricing a wallpaper project takes seconds.
- Rolls for a room
- Subtracts openings
- Roll coverage
- Waste margin
- Wall area
Last updated June 17, 2026 Feet, by wall area Reviewed by the Calcowa team
Enter a room size, wall height, and roll coverage above zero.
Each door subtracts about 21 sq ft and each window about 15. A US double roll covers roughly 50 usable sq ft; check your roll label and raise waste for a large pattern repeat.
How do you calculate wallpaper rolls?
Wallpaper is sold by the roll, so the job is to turn a room into rolls, and it's not as fiddly as it sounds. First you find the wall area: add up the length of every wall, which for a rectangular room is twice the length plus twice the width, then multiply by the wall height. Take off the doors and windows, since you won't paper over them, using about 21 square feet for a door and 15 for a window. Don't skip the waste margin, often 10 to 15 percent, because paper is trimmed top and bottom and patterned strips have to line up. Finally divide that area by the usable coverage of one roll and round up. This tool runs every step, so you'll get a roll count that already allows for openings and matching, and you don't have to sketch the walls on paper. If you're papering one feature wall, that's fine too, since you can drop the room down to a single wall.
Estimating a room, step by step
Here's the quick routine before you order, and it's just three steps:
- 1
Enter the roomType the length, width, and wall height in feet.
- 2
Add the openingsCount the doors and windows so they're subtracted.
- 3
Set roll and wasteUse your roll coverage, and raise waste for a big pattern.
Rolls by room size
Here's a rough guide for 9-foot walls, two openings, 50 sq ft rolls, and 15 percent waste. It's a starting point, so don't treat it as exact, since your roll coverage and pattern repeat won't match every product. When you're ready, run your own numbers above.
| Room | Wall sq ft | Rolls |
|---|---|---|
| 10 x 10 | 360 | 7 |
| 12 x 12 | 432 | 9 |
| 12 x 14 | 468 | 10 |
| 14 x 16 | 540 | 11 |
Frequently asked questions
You enter the room size and wall height, note any doors and windows, and it works out the rolls. It finds the wall area from the perimeter times the height, subtracts the openings, adds a waste margin for trimming and pattern matching, then divides by the coverage of one roll. Everything runs in your browser, so you'll see the roll count change as you adjust a number, and you can copy the result to take to the store.
Find the wall area, take off the doors and windows, add about 10 to 15 percent for waste, then divide by the usable coverage of a roll. A roll varies by type, so check the label, but a US double roll covers roughly 50 usable square feet after trimming. A 12 by 14 room with 9-foot walls works out near 10 rolls once you allow for waste and a couple of openings.
Wallpaper is trimmed at the ceiling and baseboard, and patterned paper has to line up from strip to strip, which wastes part of each drop. A plain or random-match paper needs only about 10 percent extra, while a large pattern repeat can push waste to 20 percent or more, since you cut to align the design. The calculator adds a margin you set, so order a little over rather than risk a dye-lot mismatch on a second trip.
The pattern repeat is the vertical distance before the design starts over, and it drives how much paper you lose matching strips. A small repeat under a few inches barely costs anything, but a large repeat means each strip starts higher or lower to line up, so you trim more off the top. If your paper lists a big repeat, raise the waste percentage here, because the longer the repeat, the more you'll set aside.
Yes, and from the same dye lot if you can, because rolls printed in different batches can differ slightly in color, which shows on a finished wall. Buy a little extra in that one order so you have a spare for mistakes or future repairs, and keep the labels. Running short later often means a new dye lot that does not quite match, so a small surplus now saves a headache.
Yes, it's completely free, with no sign-up, and it runs right in your browser, so nothing you enter leaves your device. Type the room size, the openings, and your roll coverage, and read the rolls in a tap. Bookmark it for a feature wall, a full room, or a decorating quote, and you'll have a solid roll estimate whenever you plan a wallpaper project.
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Papering a room?
Work out the rolls above, or browse all the construction tools.