Wallpaper Calculator
This wallpaper calculator turns your room perimeter, wall height and pattern repeat into the number of single rolls to buy, with the double-roll equivalent for US-packaged brands. It handles 20.5-inch Euro and 27-inch wide rolls, stretches each cut length to match the repeat, and accepts feet-and-inches or meters.
Wallpaper rolls needed
7single rolls
- Double rolls (US packaging)4
- Strips to hang26
- Cut length per strip (drop)8'
- Usable drops per roll4
- Spare strips — your waste allowance2
Formulas last reviewed on .
How the roll count is calculated
Wallpaper math is really strip math. The calculator works out how many vertical strips wrap your room, how long each one must be cut, and how many of those cuts fit on one roll:
strips = ceil(perimeter ÷ roll width)
drops per roll = floor(roll length ÷ drop)
rolls = ceil(strips ÷ drops per roll)
The drop is the cut length of one strip. Plain paper cuts at wall height, but a patterned paper must be cut in whole repeats so every strip starts on the same part of the motif — a 98-inch wall with a 24-inch repeat needs 120-inch cuts, and that extra 22 inches per strip is unavoidable scrap.
The defaults describe a Euro single roll: 20.5 inches wide by 33 feet long. Note the floor in “drops per roll” — a 33-foot roll holds four 8-foot drops and the leftover 5 feet is offcut, not a fifth strip. Deliberately, no area is credited back for doors and windows: strips over openings usually still run full length once you allow for pattern matching, and the trimmings become your repair stash.
Worked example: papering a 12 × 10 dining room
Take a 12 × 10 ft dining room with 8-foot walls, hung with a plain-textured Euro roll — 20.5 inches wide, 33 feet long, no repeat. That’s the calculator’s default setup, so the result box above is showing this exact job.
- Perimeter: 2 × (12 + 10) = 44 ft, which is 528 inches of wall to wrap.
- Strips: 528 ÷ 20.5 = 25.8, rounded up to 26 strips. That last sliver of a strip still consumes a full-length cut.
- Drop: no repeat, so each strip cuts at wall height — 96 inches.
- Drops per roll: 396 ÷ 96 = 4.1, floored to 4 usable drops per 33-ft roll.
- Rolls: 26 ÷ 4 = 6.5, rounded up to 7 single rolls — sold in the US as 4 double rolls.
Seven rolls give you 28 drops for 26 strips, so two full spare strips ride along as your allowance for a torn edge or a crooked first hang. Since we never credited the door and two windows, in practice the pieces you save there cover mistakes too — order the 7 and sleep fine.
How many rolls of wallpaper do I need for a 10×10 or 12×12 room?
Roll counts below are for 8-foot walls hung with standard Euro single rolls (20.5″ × 33 ft), at three common pattern repeats. Divide by two for double rolls, rounding up.
| Room size | Perimeter | No repeat | 12″ repeat | 24″ repeat |
|---|---|---|---|---|
| 8 × 10 ft | 36 ft | 6 | 6 | 6 |
| 10 × 10 ft | 40 ft | 6 | 6 | 6 |
| 10 × 12 ft | 44 ft | 7 | 7 | 7 |
| 12 × 12 ft | 48 ft | 8 | 8 | 8 |
| 12 × 14 ft | 52 ft | 8 | 8 | 8 |
| 14 × 16 ft | 60 ft | 9 | 9 | 9 |
| 16 × 20 ft | 72 ft | 11 | 11 | 11 |
Surprised the repeat columns match? At exactly 8-foot walls, 12- and 24-inch repeats divide evenly into the 96-inch drop, so nothing changes. The repeat bites when it doesn’t divide: give that 12 × 12 room 8′2″ walls and plain paper still needs 8 rolls, but a 24-inch repeat forces 120-inch drops — only three per roll — and the same room jumps to 10 rolls. Always run your real wall height through the calculator before ordering a patterned paper.
Frequently asked questions
What’s the difference between a single roll and a double roll?
They’re the same paper — a double roll is simply twice the length on one spool, and it’s how most US retailers actually ship. Pricing is often quoted per single roll while the checkout sells doubles, which is a classic way to under-order by half. This calculator counts in single rolls and shows the double-roll equivalent, so match whichever unit your supplier’s cart uses before you pay.
What does pattern repeat mean on wallpaper?
The repeat is the vertical distance before the design duplicates itself — it’s printed on the label, typically 0 to 25 inches. To keep the motif aligned across strips, every strip must be cut in whole repeats, so an 8′2″ wall with a 24-inch repeat gets 10-foot cuts and nearly two feet of scrap per strip. A zero repeat (textures, grasscloth-look vinyls) wastes almost nothing; a big repeat on tall walls can add whole rolls.
Why do all my rolls need the same batch or dye lot number?
Wallpaper is printed in production runs, and the ink shade shifts slightly between runs. Side by side on a wall, that tiny shift reads as an obvious vertical color band. Every roll label carries a batch (dye lot) number — check that all your rolls match before the paste comes out, and buy your spare roll now rather than later, because the same pattern reordered next month will likely arrive from a different run.
How much wallpaper paste do I need per roll?
As a rule of thumb, a gallon of ready-mixed paste hangs roughly six single rolls, and a packet of powdered paste usually mixes enough for four to eight — the tub or box states its roll coverage, so check the label against this calculator’s roll count. Porous, unprimed drywall drinks paste, so prime or size the walls first; you’ll use less and, more importantly, the paper will come off cleanly someday.
Should I subtract doors and windows from my wallpaper estimate?
Skip the credits — this calculator deliberately doesn’t take them. A strip that lands on a window still gets cut at full drop length so the pattern lines up above and below the opening; you only truly save paper on a wide patio door or a full archway. If a single doorway-heavy wall clearly saves you strips, you can shorten the perimeter you enter, but conservative ordering from the same dye lot beats a short order every time.
These results are planning estimates only — verify quantities with your supplier and local building code before you buy or build. See our terms of use.