Wallpaper Calculator: How Many Rolls of Wallpaper?

Why wallpaper is counted in drops, not square feet

Wallpaper goes up in full-height strips, called drops. A roll yields only as many whole drops as fit in its length, and the leftover piece at the end is usually too short to use. That is why dividing the wall area by the roll area often comes out one roll short. Mr Wallcover gives a clean example: a 5.00 m × 2.70 m wall on 0.53 m × 10.05 m rolls. By area that is 13.5 m² ÷ 5.33 m², under 3 rolls. By drops it is 10 drops at 2.80 m each, three per roll, so 4 rolls.

The calculator therefore works drop by drop:

1. Drops = wall width ÷ roll width, rounded up. A part-width strip still uses a full-length drop.
2. Cut length = height to paper + trim at top and bottom (2 in each by default).
3. Drops per roll = how many cut lengths fit in the roll, allowing for the pattern match (below), rounded down.
4. Rolls = drops ÷ drops per roll, rounded up, plus a spare.

Doors and windows are left in. You still cut full drops above and below them, and the offcuts rarely make a whole strip. Only skip a full-height opening, such as a wide archway or a sliding door, where no paper goes at all.

Pattern repeat and match: straight, half-drop and free

The repeat is the vertical distance before the design starts again, printed on the label or product page in inches or centimeters. The match tells you how neighboring drops line up.

• Free or random match (stripes, textures, grasscloth): no pattern to line up, so drops are cut back to back. Waste is lowest.
• Straight match: the design runs straight across the seam, so every drop starts at the same point in the pattern. Each drop on a roll begins a whole number of repeats after the last one, and the first repeat of every roll is lost finding the pattern. Mr Wallcover’s example: a 2.65 m high wall, 10 cm trim and a 65 cm repeat give a 2.75 m drop that takes 3.25 m of roll; three fit in 10 m.
• Half-drop match: every other drop is shifted down by half a repeat, so the design runs diagonally. Drops alternate between two starting points. You can cut alternately along each roll, or cut the “A” drops from some rolls and the “B” drops from others. The calculator works it out both ways and keeps the one that needs fewer rolls.

A large repeat can cost a drop per roll. On a US double roll (33 ft) with 9 ft walls and 4 in of trim, a 25 in repeat still yields three drops, but a 27 in repeat drops it to two, so the same room suddenly needs about 50% more rolls. The area method below hides that jump, which is the main reason to count drops.

Roll sizes: single, double and Euro rolls

In North America, wallpaper is often priced per single roll but packed and shipped as a double roll, one continuous piece twice as long. Wallpaper Warehouse and Tempaper both list a double roll at 20.5 in × 33 ft, about 56 sq ft. Check whether the price shown is per single or per double roll. Farrow & Ball and most European papers come in 10 m × 53 cm rolls. If yours is different, choose Custom and enter the width and length from the label.

The quick area check, and how much spare to buy

Many US guides use an area shortcut instead. The No Two Houses guide measures the walls, subtracts 21 sq ft per door and 15 sq ft per window, and divides by the usable yield of a roll: 50 sq ft for repeats up to 6 in, 44 sq ft for 7–12 in, 40 sq ft for 13–18 in and 36 sq ft for 19–23 in. The calculator shows that figure beside the drop count for US double rolls. When the two disagree, trust the drop count, because it follows how the paper is actually cut.

Order at least one spare roll. Farrow & Ball and Mr Wallcover both recommend it for trimming errors and repairs, and because rolls from different production runs can differ slightly in color. Buy every roll from the same batch (the batch or run number is on the label) and check it before you cut. Hang the first few drops, then stop and look at the seams and the shade in daylight.

For patching first, see the drywall mud calculator; to paint instead, the paint calculator uses the same room measurements.

Sources & assumptions

How this calculator gets its numbers. Full method: our methodology.

• Drops = wall width ÷ roll width, rounded up. Cut length = height to paper + trim (default 4 in, 2 in top and bottom).
• Free match: drops per roll = roll length ÷ cut length, rounded down. Straight match: one repeat is lost at the start of each roll, then each drop starts a whole number of repeats after the last (the method Mr Wallcover describes).
• Half drop: the calculator tries cutting alternate drops along each roll (each start half a repeat out of phase) and cutting each phase from its own rolls, and keeps whichever needs fewer rolls.
• Rolls = drops ÷ drops per roll, rounded up, plus spare rolls (default 1, as Farrow & Ball and Mr Wallcover advise). Full-height openings you enter are skipped; normal doors and windows are left in.
• The area check, for US double rolls only, follows No Two Houses: subtract 21 sq ft per door and 15 per window and divide by 50, 44, 40 or 36 usable sq ft per roll for repeats of 0–6, 7–12, 13–18 and 19–23 in.
• Roll sizes: US double 20.5 in × 33 ft (about 56 sq ft), wide double 27 in × 27 ft, single 20.5 in × 16.5 ft (Tempaper, Wallpaper Warehouse); Euro 53 cm × 10 m (Farrow & Ball). Check the label of the paper you buy.

Sources

1. Mr Wallcover, How much wallpaper should you order?. Count drops, not area; 5 cm trim top and bottom; worked examples (5.00 × 2.70 m wall: 10 drops, 3 per roll, 4 rolls; 65 cm straight repeat: 3 drops per roll); half-drop phases; one spare roll from the same batch.
2. Farrow & Ball, Calculating Wallpaper Quantities. Rolls 10 m × 53 cm; drops per roll for small and large repeats in a 2.4 m room; add one more roll.
3. No Two Houses, Wallpaper Guide (2025). Subtract 21 sq ft per door and 15 per window; usable yield per roll 50 / 44 / 40 / 36 sq ft for repeats of 0–6 / 7–12 / 13–18 / 19–23 in; free, straight and drop matches.
4. Tempaper & Co., FAQ: roll sizes. Double rolls 20.5 in × 11 yd (56.4 sq ft) or 27 in × 9 yd (60.8 sq ft); single roll 20.5 in × 16.5 ft (28.2 sq ft).
5. Wallpaper Warehouse, Single Roll vs. Double Roll Wallpaper. Single roll 20.5 in × 16.5 ft (~28 sq ft), double roll 20.5 in × 33 ft (~56 sq ft); single-roll prices still mean buying double rolls.

Last reviewed October 27, 2026. Product figures vary by brand; the label on what you buy wins.