Wallpaper Calculator
Estimate how many rolls of wallpaper you need for a wall or whole room, with an allowance for pattern repeat and trimming waste.
This calculator estimates how many rolls of wallpaper you need. Measure each wall's width and the wall height in feet, tell the calculator the roll's usable coverage, and choose a waste level based on your pattern. The result rounds up to whole rolls.
Enter your wall measurements and roll coverage to see how many rolls you need.
How the wallpaper calculator works
- Wall area = total wall width × wall height. 40 ft × 8 ft = 320 sq ft.
- Add pattern waste. At 15%, that becomes 368 sq ft of paper to buy.
- Divide by usable coverage per roll and round up. 368 ÷ 56 = 6.6, so buy 7 rolls.
Hanging tips
- Read the label first for usable coverage, repeat size, and match type (straight vs. drop match).
- Buy one extra roll from the same batch for mistakes and repairs.
- Prep the wall — clean, smooth, and primed surfaces hold paper far better.
- Plan your starting seam in an inconspicuous corner so the inevitable pattern mismatch is hidden.
Two worked examples
Example 1 — a feature wall. A single 12 ft wide wall at 8 ft tall is 96 sq ft. Subtract nothing if it is solid, add 15% for a small repeat: 96 × 1.15 = 110 sq ft. With double rolls that cover about 56 usable sq ft, 110 ÷ 56 = 1.97, so you buy 2 rolls — and a third if the pattern repeat is large.
Example 2 — a full bedroom. Four walls totaling 48 ft of width at 8 ft tall is 384 sq ft gross. Subtract one door (21 sq ft) and two windows (15 sq ft each) for 51 sq ft, leaving 333 sq ft. Add 15% pattern waste: 333 × 1.15 = 383 sq ft. At 56 sq ft per roll, 383 ÷ 56 = 6.8, which rounds up to 7 rolls. A large repeat at 25% waste would push the same room toward 8 rolls.
Cost and planning factors
Roll count is only half the budget. The paper itself spans a wide range — prepasted standard papers sit at the low end, while designer prints and textured grasscloth cost considerably more per roll. Beyond the rolls, plan for primer or wallpaper sizing to help adhesion and future removal, separate paste if your paper is unpasted, and a basic tool kit (a smoother, a seam roller, a sharp blade, and a level). Pattern repeat is the quiet cost driver: the larger the repeat, the more you trim from each strip to line it up, which is why big repeats carry higher waste percentages. Always buy from one batch number and keep a spare roll for repairs.
Wallpaper costs in 2026
Wallpaper cost depends on the paper you choose and whether you hang it yourself.
| Cost item | Notes |
|---|---|
| Wallpaper rolls | Prepasted (lower) → designer / grasscloth (higher) |
| Primer / wallpaper size | Helps adhesion and future removal |
| Adhesive (if unpasted) | Some papers need separate paste |
| Tools | Smoother, seam roller, sharp blade, level |
| Labor (if hiring) | Rises with large pattern repeats |
Wallpaper and labor prices vary by product and region — these are planning factors, not a quote.
Common mistakes to avoid
- Under-ordering — large pattern repeats waste more paper per strip.
- Mixing rolls from different batch numbers, so colors don't match.
- Hanging over unprimed or dirty walls, so seams lift later.
- Forgetting to subtract big openings, or over-trusting a low roll count.
- Starting the first seam in a visible spot instead of a hidden corner.