Wallpaper Calculator: How Many Rolls of Wallpaper You Need
Work out how many rolls of wallpaper a room needs from wall sizes, doors, windows, roll size and pattern repeat, counted strip by strip. Enter the room or each wall, the height, the doors and windows, pick a US double roll or a European roll and the pattern match, and get the strips, the strips per roll, the rolls with a spare, an area check and the cost.
Your numbers
All four walls: the perimeter is 2 × (length + width).
A 36 × 80 in door is 20 sq ft.
On the roll label. A straight match lines up across every strip; a half-drop lines up every second strip.
Extra cut at the top and bottom of each strip, about 2 in at each end.
About 10% covers a mistake and a later repair from the same batch.
From the paste label. Leave empty for prepasted or paste-the-wall paper that comes with its own.
Rolls needed
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- With 10% spare
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- Strips to hang
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- Strips per roll
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- Wall area to cover
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- Area check
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- Cost with spare
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The strip count is the number to buy from; the area check is lower because it ignores the offcut at the end of each roll. Buy every roll from one batch (lot) number.
The calculation runs in your browser and ParrotNotes does not store your numbers. They sit in the page address so you can bookmark or share the result.
How to use the wallpaper calculator
Choose Whole room and enter the room's length and width, or Separate walls and enter each wall's width, for a feature wall or a room with a sloped side. Enter the wall height, the number of doors and windows, the roll size and the pattern match from the label. The trim allowance is the extra cut off at the top and bottom of each strip.
Worked example: a 14 × 12 ft room, 8 ft walls, one door and two windows, US double rolls of 20.5 in × 33 ft, no pattern match. The perimeter is 52 ft (624 in), which is 31 strips; the door and windows cover 50 sq ft, worth 3 full strips at 8 ft, so 28 strips. Each strip is 96 in plus 4 in of trim, so a 396 in roll gives 3. 28 ÷ 3 rounds up to 10 rolls, and with 10% spare you buy 11.
Why the calculator counts strips
Wallpaper goes up in full-height strips, side by side. The width of the wall sets how many strips you hang; the height of the wall sets how many strips you get out of one roll. What is left at the end of a roll is usually too short for another strip, so dividing the wall area by the roll area undercounts. The area check is still shown, as the floor: if it says 6.5 rolls and the strips say 10, the gap is offcut.
Doors and windows are taken off as whole strips only. The paper above a door and below a window still has to be cut and hung, often from the offcuts, so a door does not save its full area. For a room with many large windows or a wall of built-in shelves, measure the papered sections as separate walls instead.
Pattern repeat and match
The label gives the repeat, the height of one cycle of the design, and the match. With no match (plain papers, stripes, random designs) strips can be cut end to end. With a straight match each strip starts at the same point of the design. With a half-drop every second strip starts half a repeat lower. In both cases the cut between strips moves on to the next match point, and the paper in between is lost.
A small repeat costs little; a large one can cost a strip per roll. On a 33 ft roll with 8 ft walls, a 24 in repeat still gives 3 strips per roll. With 90 in strips (a 7 ft 2 in wall plus 4 in of trim), a 24 in straight match gives 4 strips, while a 36 in straight match drops to 3.
Before you order
Buy every roll from the same batch or lot number, printed on the label: colors can differ between print runs. The spare covers a miscut strip and a later repair. Check whether the paper is prepasted, paste-the-wall or needs paste, and count packets from the paste label if it does.
Paint, drywall and floor area
If the other walls get paint, the Paint Calculator works out gallons from the same room size, doors and windows. The Square Footage Calculator adds up awkward rooms section by section, the Drywall Calculator counts sheets for a new wall before it is papered, and the Flooring Calculator does the floor of the same room.
For painters, decorators and installers
A wallpaper quote is built on site: the wall widths, the ceiling height, the paper the client picked and its repeat, which walls get it, and what has to be stripped first. Get one measurement wrong and the order is short, often by rolls from a batch that is no longer in stock.
Sources, each read on 2026-10-23. All results are estimates; the roll label and your retailer decide:
More for home improvement pros: Home improvement sales, Quote follow-up email.
The room is measured on the visit
Wall widths, the ceiling height, which wall gets the feature paper and where the outlets are get said out loud while you walk the room. Record the visit in ParrotNotes and get a transcript, a summary and the action items, so the order and the quote match what was measured.
Get Started FreeRelated tools
- Paint CalculatorWork out how many gallons of paint a room needs from the walls, doors, windows and coats, and what it will cost.Open the tool
- Square Footage CalculatorWork out square footage for rectangles, L-shaped rooms, triangles and circles, add rooms together, and convert to square yards, square meters and acres.Open the tool
- Drywall CalculatorEstimate how many drywall sheets a room needs from its walls and ceiling, with joint compound, tape, screws and the cost.Open the tool
- Flooring CalculatorWork out how much flooring a room needs in square feet and boxes, with waste for the layout, underlayment, trim and cost.Open the tool