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How wallpaper rolls are estimated
This calculator finds the gross wall area — 2 × (length + width) × height — then subtracts doors (21 sq ft each) and windows (15 sq ft each) to get the net paperable surface. If you tick pattern matching, it adds a further 10% because patterned paper needs extra length to align repeats across strips. The final area is divided by the coverage per roll and rounded up to the next whole roll.
Roll sizes vary by region. In the United States, wallpaper is commonly sold as a double roll covering about 56 sq ft (a single roll ≈ 28 sq ft), which is our default. European and metric rolls differ — typically about 5.3 m² (≈ 57 sq ft) — so always check the label on your specific roll and adjust the coverage field.
Pattern repeat matters. Large repeats (say, 24 in or more) waste noticeably more paper than a random or small repeat. If your pattern has a big drop match, add 15–20% rather than the default 10%. Always buy from the same dye lot so colors match across rolls.
Prep and measuring tips
Wallpaper is unforgiving, so measure carefully: record the height of every wall (not just one) and the exact widths of doors and windows you'll paper around. It's usually easier to paper a freshly primed, smooth surface than to fight a textured or glossy one. Keep at least one extra roll beyond your estimate — returns are rarely possible once a dye lot sells out, and a spare roll is essential for future repairs.
More material tools
- Paint calculator — gallons of paint for your walls.
- Flooring calculator — boxes of tile or flooring.
- Curtain fabric calculator — fabric panels and yardage.