Wallpaper Roll Calculator
Find out exactly how many wallpaper rolls you need for your room or wall — including pattern repeat and wastage — so you never run short mid-project or overbuy.
- Exact rolls needed (no wastage)0
- Wall strips needed0
- Strips you get from one roll0
- Total wall area to cover0
- Total wall width0
Estimates assume straight walls. Always round up and keep one spare roll from the same dye lot for future repairs.
How the wallpaper calculation works
Wallpaper is sold by the roll, but walls are covered in vertical strips. The calculator figures out how many strips your walls need, then how many strips each roll gives you:
2. Strips per roll = roll length ÷ (wall height + pattern repeat + trimming) (rounded down)
3. Rolls needed = strips needed ÷ strips per roll (rounded up)
Worked example
A 12 × 10 ft room with 8 ft ceilings, 1 door and 2 windows, using standard US rolls (20.5 in × 33 ft) with a 12-inch pattern repeat:
- Wall width to cover: 2 × (12 + 10) − 3 − 8 = 33 ft
- Strips needed: 396 in ÷ 20.5 in = 20 strips
- Strips per roll: 396 in ÷ (96 + 12 + 2) in = 3 strips
- Rolls: 20 ÷ 3 = 7 rolls, plus 10% wastage = 8 rolls to buy
Quick reference: common US roll sizes
| Roll type | Width | Length | Covers about |
|---|---|---|---|
| US double roll (standard) | 20.5 in | 33 ft | 56 sq ft |
| US single roll | 20.5 in | 16.5 ft | 28 sq ft |
| European roll | 21 in | 33 ft | 57 sq ft |
Pro tips before you buy
- Check the dye lot. Buy all rolls at once so the batch numbers match — colors can vary slightly between lots.
- Mind the repeat. A large 24-inch repeat can add 2–3 extra rolls versus a no-pattern paper in the same room.
- Measure twice. Walls are rarely perfectly straight; always use your tallest height measurement.
- Keep a spare roll. One leftover roll is cheap insurance for future scuffs and repairs.
Frequently asked questions
How many wallpaper rolls do I need for a 12x12 room?
A 12x12 ft room with 8 ft ceilings, one door and one window needs about 8 rolls of standard US wallpaper (20.5 in × 33 ft) with no pattern repeat, or about 10–11 rolls with a 12-inch pattern repeat. Enter your exact measurements above for a precise number.
What is pattern repeat and why does it matter?
Pattern repeat is the vertical distance before a wallpaper pattern starts over — for example 12 or 24 inches. Each strip must be cut longer by one repeat so the pattern lines up from strip to strip, which means fewer strips per roll and more rolls needed overall. Always check the repeat printed on the roll label.
What is the standard wallpaper roll size in the US?
The standard US double roll is 20.5 inches wide and 33 feet long, covering about 56 square feet. A single roll is 20.5 inches wide and 16.5 feet long. European rolls are commonly 21 inches wide and 33 feet long.
Should I buy extra wallpaper rolls?
Yes — buy 10% extra (usually one spare roll) to cover cutting mistakes and future repairs. Rolls from different dye lots can look slightly different, so having spare rolls from the same batch matters.
Do I subtract doors and windows when calculating wallpaper?
Yes. Subtract about 3 ft of width per door and 4 ft per window from your total wall width. The calculator does this automatically in Room mode. The 10% wastage allowance covers the strips above and below windows.
How do I measure a room for wallpaper?
Measure the width of each wall in feet and the ceiling height, then add the wall widths together. Count the doors and windows. Measure twice and use the tallest height — walls and ceilings are rarely perfectly level.
How many rolls do I need for one accent wall?
Measure just that wall and use "Single wall / walls" mode above. A typical 12 ft wide, 8 ft tall accent wall needs 3 rolls of standard US wallpaper with no pattern repeat, or 4 rolls with a 12-inch repeat (including wastage).
Does ceiling height change how many rolls I need?
Yes, a lot. Taller walls mean longer strips, so each roll yields fewer strips. A room with 10 ft ceilings can need 30–40% more rolls than the same room with 8 ft ceilings, especially with a large pattern repeat.