Wallpaper Calculator

Step 1: Choose Imperial or Metric. The calculator switches all units (length, area, roll size, pattern repeat) so the result is in gallons-or-liters-equivalent terms — rolls — and area shows in your familiar unit.

Step 2: Measure each room. Enter length, width, and ceiling height in feet (or meters). Click "+ Add Room" if you are wallpapering more than one room with the same paper. You can rename each room (Bedroom, Living Room) for the breakdown table.

Step 3: Enter doors and windows per room. The defaults assume a standard 80 × 36 inch interior door (20 sqft / 1.86 sqm) and 36 × 48 inch window (12 sqft / 1.11 sqm). The calculator subtracts these from the wall area you need to cover.

Step 4: Choose your roll size. The standard global roll is the EU single roll (10.05 m × 0.53 m), which equals roughly 57 sqft. The US double roll (33 ft × 27 in ≈ 74 sqft) is the most common American size. The US single roll (16.5 ft × 27 in) is half a double roll and now uncommon. Choose Custom if your paper has unusual dimensions.

Step 5: Set the pattern repeat. Pattern repeat is the vertical distance after which the pattern starts again. Each strip needs to be cut taller than the wall by exactly this amount so the pattern aligns with the previous strip. Choose None for plain wallpaper, or select a category that matches the pattern repeat printed on your wallpaper sample roll (printed as something like "pattern repeat: 12 in" on the label).

Step 6: Adjust the waste percentage. The default is 10 percent extra, which covers trim, accidental tears, and saving a spare strip for future touch-ups. For complex rooms with many corners and openings, 15 to 20 percent is safer.

Step 7: Optionally enter the price per roll for a total cost estimate.

Step 8: Click Calculate. The calculator shows rolls needed (always rounded up — you cannot buy partial rolls), per-room breakdown, a floor plan, and step-by-step math.

Wallpaper is sold by the roll, but you do not get to use every square foot of paper in a roll. The math has three sources of waste that area-based calculators usually ignore:

Pattern repeat waste. Patterned wallpaper has a vertical repeat — a distance after which the pattern starts again. To make adjacent strips line up, each strip must be cut taller than the wall by exactly the pattern repeat. If your wall is 8 ft and the pattern repeats every 6 inches, each strip needs to be 8.5 ft of paper for only 8 ft of wall use. That means 6 inches of paper is wasted at the top of every strip.

End-of-roll waste. Once you've cut as many strips of the required height as the roll allows, anything shorter than a full strip is unusable for pattern matching. A 33 ft (US double) roll at 8.5 ft strip height yields floor(33 / 8.5) = 3 strips, leaving 7.5 ft of paper that you can't use for new wall strips.

Trim and mistake waste. Real-world wallpapering involves trimming around corners, doorframes, light switches, and occasionally cutting a strip incorrectly. The standard recommendation is 10 percent extra paper for typical rooms, 15 to 20 percent for rooms with many openings.

Why per-room math is more accurate. Wallpaper from different production batches ("dye lots") rarely matches in color exactly, so you can't always combine leftover material from one room into another room reliably. The calculator computes rolls per room separately, which sometimes adds 1 extra roll versus a single combined calculation — but ensures you have matching paper for each project.

Roll sizes vary by market. The EU single roll (10.05 m × 0.53 m / 5.33 sqm) is the global standard outside North America. The US double roll (33 ft × 27 in / 74.25 sqft) is the typical American size. Confusingly, US "single rolls" (16.5 ft / 37 sqft) are now rare — most American wallpaper is sold in double-roll bolts but priced per single roll, so always check the label. European rolls are usually sold individually with consistent dimensions.

For each room with length L, width W, ceiling height H, doors D, windows N:

Wall area = 2 × (L + W) × H

Net wall area = Wall area − (D × door area) − (N × window area)

(Default door area = 20 sqft / 1.86 sqm; default window area = 12 sqft / 1.11 sqm.)

Strip height = H + pattern repeat (the per-strip allowance for pattern matching)

Strips per roll = ⌊Roll length / Strip height⌋ (integer — any partial leftover strip at the end of a roll cannot be used for pattern-matched work)

Usable coverage per roll = Strips per roll × H × Roll width (only the H portion of each strip actually appears on the wall — the pattern-repeat portion is the cutting overhead)

Rolls needed for room = ⌈Net wall area × (1 + waste %) / Usable coverage per roll⌉

Total rolls = sum of rolls across all rooms (rounded per room because rolls are bought whole).

Example: 12 × 12 × 8 ft bedroom, 1 door, 2 windows, 6-inch pattern repeat, US double roll, 10% waste.
- Wall area = 2 × (12 + 12) × 8 = 384 sqft
- Net = 384 − 20 − 24 = 340 sqft
- Strip height = 8 + 0.5 = 8.5 ft
- Strips per roll = ⌊33 / 8.5⌋ = 3
- Usable per roll = 3 × 8 × 2.25 = 54 sqft
- Rolls = ⌈340 × 1.10 / 54⌉ = ⌈6.93⌉ = 7 rolls

Example 1: Plain wallpaper (no pattern). Bedroom 12 × 12 × 8 ft, 1 door, 2 windows, US double roll. Strip height = 8 ft, strips per roll = ⌊33 / 8⌋ = 4. Usable per roll = 4 × 8 × 2.25 = 72 sqft. Rolls = ⌈340 × 1.10 / 72⌉ = ⌈5.19⌉ = 6 rolls. Plain wallpaper saves 1 roll vs the same room with a 6-inch pattern repeat.

Example 2: Living room with pattern. 16 × 14 × 9 ft, 1 door, 3 windows, US double roll, 12-inch pattern repeat. Wall area = 540 sqft. Net = 540 − 20 − 36 = 484 sqft. Strip height = 9 + 1 = 10 ft. Strips per roll = ⌊33 / 10⌋ = 3. Usable per roll = 3 × 9 × 2.25 = 60.75 sqft. Rolls = ⌈484 × 1.10 / 60.75⌉ = ⌈8.76⌉ = 9 rolls.

Example 3: Three-room project. Bedroom (12×12×8), living room (16×14×9), hallway (4×16×9). Same wallpaper throughout, US double roll, 6-inch pattern repeat. Per-room: bedroom = 7 rolls (from example above), living room = 9 rolls. Hallway: walls = 2 × (4+16) × 9 = 360 sqft − 1 door = 340 sqft net, strip = 9.5, strips/roll = 3, usable/roll = 60.75, rolls = ⌈340 × 1.10 / 60.75⌉ = ⌈6.16⌉ = 7. Total: 7 + 9 + 7 = 23 rolls. Order all from the same dye lot batch for color consistency.

Buy from the same dye lot. Wallpaper printed in different production runs has slight color variation. Note the batch number on each roll's label and verify all rolls match before opening. If you need extra rolls later, the dye lot is often unavailable — buy 10–20 percent more upfront.

Don't trust the roll's printed coverage. Manufacturer-stated "covers X sqft" assumes plain wallpaper without pattern repeat. Once you account for pattern repeat plus end-of-roll waste, real usable coverage is 70–85 percent of stated coverage.

Pattern repeat is printed on the roll label. Look for "vertical repeat" or "pattern repeat" in inches or centimeters. Common values: 6 in, 12 in, 18 in, 24 in. Random-match (no repeat) wallpaper has no pattern alignment requirement and is the most paper-efficient.

Drop match doubles the repeat allowance. A "straight match" pattern aligns strips at the same point. A "half-drop match" alternates strips by half the pattern length — the effective repeat allowance is 1.5× the printed repeat. For drop-match patterns, add 50 percent to the pattern repeat number on the label, or use the next-larger pattern preset in this calculator.

Use full strips at the most-visible wall. When you have leftover paper, use it on the wall behind furniture or in low-light corners. The strips that have visible pattern joins should come from the first, freshest cuts.

Store extra rolls properly. Keep unused rolls upright in a dry, temperature-stable space. Wallpaper that has rolled lying flat for years can warp at the edges and become impossible to hang flat.

Glue paste vs prepasted. Prepasted wallpaper (activate by wetting) is now standard for residential. Paste-the-wall and paste-the-paper require separate paste purchase — typical 1 gallon of paste covers 3 to 5 double rolls.