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Wallpaper Calculator
Calculate how many wallpaper rolls you need from room perimeter, wall height, doors, windows, and pattern repeat. Includes waste for pattern matching.
Estimate only — roll coverage varies by brand and pattern. Always verify with your specific wallpaper product's coverage chart.
About This Calculator
Enter your room's total wall perimeter, ceiling height, and the number of doors and windows, and this calculator estimates exactly how many wallpaper rolls you need — including extra for pattern matching. Works with any US double roll (standard 56.6 sq ft coverage) or a custom roll size from your specific wallpaper brand.
How It Works
Gross wall area = perimeter × wall height. Deductions = doors × 21 sq ft + windows × 15 sq ft. Net area = gross − deductions. Pattern waste factor: none = ×1.00, small repeat (< 6 in) = ×1.10, medium (6–12 in) = ×1.20, large (> 12 in) = ×1.30. Rolls needed = net area × waste factor ÷ roll coverage. Rolls to buy = ⌈rolls needed⌉ (always round up).
The Formula
rolls = ⌈(P × H − D×21 − W×15) × F ÷ R⌉
- P
- room perimeter (ft)
- H
- wall height (ft)
- D / W
- door count (21 sq ft each) / window count (15 sq ft each)
- F
- pattern waste factor (1.00–1.30)
- R
- roll coverage (sq ft) — US double roll ≈ 56.6 sq ft
Frequently Asked Questions
- What is a standard US double roll of wallpaper?
- Most US wallpaper is sold in double rolls with approximately 56 to 57 square feet of usable coverage (the industry norm is 56.6 sq ft). The single-roll pricing is often displayed for marketing purposes, but the product is physically a double roll. Always check the specific product's coverage specification — European and Asian imports commonly use different roll widths.
- Why subtract area for doors and windows?
- Standard interior doors are approximately 21 square feet (3 ft × 7 ft) and standard double-hung windows are approximately 15 square feet (3 ft × 5 ft). Subtracting these avoids purchasing rolls that cover areas you cannot wallpaper. For very large or very small openings, adjust the totals manually.
- What pattern repeat should I choose?
- No pattern (solid or random): select 'none' (×1.00 factor). Small repeat under 6 inches: select 'small' (×1.10). Medium repeat 6–12 inches: select 'medium' (×1.20). Large repeat over 12 inches: select 'large' (×1.30). The pattern repeat is printed on the wallpaper label. Large repeats require aligning each strip, which wastes more material per strip.
- How do I calculate my room's perimeter?
- Add the length of all four walls. For a 12 ft × 14 ft room, perimeter = 12 + 14 + 12 + 14 = 52 ft. For non-rectangular rooms, measure each wall segment and add them all. Do not subtract doors and windows when entering the perimeter — the calculator handles those deductions separately.
Estimates only. Coverage figures (sq ft/gallon, bag yield, BTU/sq ft) are industry rules of thumb with real-world variance. Verify quantities with your supplier before purchasing.