Wallpaper calculator: how many rolls to buy?
Strips, then rolls, from your walls and the label. Free, no sign-up, nothing leaves your browser.
Example, not your room
Still needed
Example numbers9 rolls
13 ft x 11 ft 6 in bedroom, 8 ft walls, one door and one window
Label: 20.5 in x 33 ft, 24 in repeat, half-drop match
By area alone it looks like 7. With 4 in of trim each strip takes 100 in, so a 33 ft roll gives 3 strips.
Type your walls and your label to count yours.
The rolls show once every field above is filled in or removed.
Half-drop: a check of this method on October 8, 2026 found cases where rolls that start off the pattern need one roll more than this count. Consider one spare roll.
Buy every roll from one batch or run number. A roll from another batch may not match.
Not counted here: paste for unpasted paper, primer or sizing, liner paper, borders and tools.
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Clear every wall, opening and label figure?
Measure every wall, copy the label exactly, and check the count with your store or installer before you order.
How the wallpaper calculator works
Your label gives you four figures: the roll's width and length, the pattern repeat and the match. The calculator uses all four, and it counts in strips, since strips are what you hang.
First, strips across. A single wall is its width divided by the roll width, rounded up. A room is walked corner to corner, the way a hanger works it. The strip that reaches each corner turns about an inch (25 mm) onto the next wall, and the piece cut off it starts the next wall only if it's at least half a roll wide. That's Graham & Brown's own rule. The calculator starts from whichever corner costs you the most paper, so the count never depends on picking a lucky corner.
Doors and windows come off in whole strips only, the way York's own roll calculator counts them: a 46 in window on 20.5 in paper saves two. For the paper above and below an opening, the calculator assumes it comes from the ends of your rolls.
Then the cut. Every strip is the wall height plus 4 in of trim. York's installation guide allows about that much, roughly 2 in at the ceiling and 2 in at the baseboard. Graham & Brown says the first strip should be the height of the wall plus four inches. With a straight match each strip starts at the same point in the pattern. With a half-drop every other strip starts half a repeat lower. The calculator lays the strips out along one roll in that order and counts what fits.
That's where the square-foot shortcut comes apart. An 8 ft wall plus trim needs a 100 in strip, and a 33 ft roll is 396 in long: three strips and a leftover nobody can hang. Divide wall area by roll area and the 13 ft by 11 ft 6 in example bedroom comes out at 7 rolls. Count strips and it's 9, and those two extra rolls are the ones you'd otherwise be reordering halfway through the job, hoping the new batch matches.
A new roll's pattern can start anywhere, so a roll can lose up to one repeat, or half of one for a half-drop, before the first cut. When that loss would cost a strip, you get two numbers instead of one. The low end assumes every roll starts right on the pattern. The high end lets each roll lose up to that much before its first cut.
Who this is for
You've picked a paper for a bedroom, a powder room or one accent wall, and now the order form wants a number. You've got a tape measure, the label or the product page, and maybe a count from the store that you'd like to check before you pay for it.
Painting the walls you're not papering? The paint calculator works out gallons, and the drywall calculator handles new walls before either one goes on.
Homeowner questions about wallpaper
How many rolls of wallpaper do I need?
Count strips, not square feet. Divide each wall's width by the roll width and round up, take out whole strips for doors and windows, then see how many strips of wall height plus trim fit on one roll. A 13 by 11 ft 6 in bedroom with 8 ft walls, a door and a window needs 27 strips of 20.5 in paper. A 33 ft roll gives three, so you're buying 9 rolls. Wall area over roll area would have told you 7.
How many rolls of wallpaper for a 12x12 room?
Ten double rolls of 20.5 in x 33 ft, with 8 ft walls and nothing cut out. A 32 in door and a 46 in window bring it to 9. The match doesn't move either count here: random match, or a 24 in repeat hung straight or as a half-drop, comes out the same. The roll size does. The same room in 27 in x 27 ft rolls takes 8 with random match, 8 to 11 with a 21 in straight repeat, and 11 with a 21 in half-drop.
How much wallpaper do I need for one wall?
Strips across the wall first, then strips per roll. A 12 ft wall is 144 in, so 20.5 in paper takes 8 strips. If the wall is 10 ft high, each strip is 124 in with trim. With a 24 in straight repeat a 33 ft roll holds two of them, so you need 4 rolls. As a half-drop the same roll holds three when it starts on the pattern, which makes it 3 to 4.
How many strips of wallpaper are in one roll?
Divide the roll length by the wall height plus trim, then allow for the pattern. A 33 ft roll is 396 in. On 8 ft walls each strip needs 100 in, so three fit and 96 in is left, too short for a fourth. With a 24 in half-drop the three strips start at 0, 108 and 216 in, and 80 in is left.
How many square feet does a double roll of wallpaper cover?
Width times length, before anything is cut. York's Charm paper comes as a 20.5 in x 33 ft double roll, which is 56.38 sq ft, and its product page rounds that to "about 56.4". Graham & Brown's Terrazzo page says each roll "equals a double roll" and covers "up to 56" square feet. On 8 ft walls that same 33 ft roll hangs three strips, which is 41 sq ft of wall. That gap is why area alone runs short.
What does pattern repeat mean on wallpaper?
It's how far down the roll the design goes before it starts again: "the vertical distance between one point in the pattern and where that identical point appears again," in Graham & Brown's words. A label may write the drop beside the repeat, as in 64/32: a 64 cm repeat hung with a 32 cm drop. Type 64 cm as the repeat and pick Half-drop. 64/0 means no drop, so it's a straight match.
What does half drop mean on wallpaper?
Every other strip starts half a repeat lower, so the design runs on a diagonal. Labels call it half-drop, drop or offset match. It changes the cutting as well as the look. On a 10 ft wall a 24 in repeat fits three strips on a 33 ft roll as a half-drop, and only two as a straight match. Drops other than half aren't counted here.
Do you subtract doors and windows when measuring for wallpaper?
Only in whole strips, the way York's own roll calculator counts them. A 32 in door on 20.5 in paper saves one strip, and a 46 in window saves two. The paper above and below them still has to come from somewhere, and the calculator assumes it comes from the ends left on your rolls. A wide, short window is the exception: the pieces over and under it eat most of a strip, and the calculator warns you when that happens.
How much extra wallpaper should I order?
The count already includes trim, pattern matching and the waste at the corners, so there's no percentage to add on top. A spare roll is for repairs and for a strip that goes wrong, and it should share the batch number of the rest. Add spares under Trim and spare rolls. We won't guess the number for you: it depends on how much you trust your own cutting.
Does the wallpaper batch number matter?
Yes. Graham & Brown warns that paper from another batch "may not match up with the wallpaper that's on your walls." Check that every roll carries the same batch or run number before you open a single one. Then write the number down, in case you need another roll later.
How to measure for wallpaper
Measure each wall across at its widest, and the height from the floor to the ceiling at its highest point. Write feet and inches the way the tape shows them. If wall heights differ, enter each wall separately with One wall.
Measure doors and windows across the outside of the trim, where the paper will stop. Only their width matters for the count. The height is there to catch a window that leaves most of a strip above and below it.
Then copy four figures off the label: width, length, repeat and match. Copy them exactly as printed: 20.5-in, 33-ft and 52 cm all work, and each one is shown back to you the way the calculator read it. Before you open a single roll, check that the batch numbers match.
Sources and last checked
- Trim allowance, 4 in per strip (2 in at the ceiling, 2 in at the baseboard): York Wallcoverings, Installation Guide; Graham & Brown, Wallpaper FAQ, which gives the same four inches for the first strip.
- Corner turn of 25 mm, and reusing an offcut only when it is half a width or more: Graham & Brown, Wallpaper FAQ.
- Openings taking out whole roll widths only: York Wallcoverings' product-page roll calculator.
- The pattern repeat definition and the batch warning: Graham & Brown, Wallpaper FAQ.
- Roll size and coverage figures (20.5 in x 33 ft, about 56.4 sq ft; up to 56 sq ft): York Wallcoverings, Charm Wallpaper product page; Graham & Brown, Terrazzo Pink product page.
- The repeat-and-drop notation (64/32): new-walls.com, "Wallpapering with repeat".
- Length conversions (1 in = 2.54 cm exactly): NIST Handbook 44 (2026), Appendix C.
Last checked: October 8, 2026 (wallpaper conventions and unit definitions versions 2026-10-07).
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