Wallpaper Calculator: How Many Rolls?
Calculate full wallpaper drops by wall length and the number of drops available from each roll.
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How to measure
Measure the width of every wall to cover and add those widths. Measure the full drop height from the hanging start to the finish point. Use the physical roll width in inches and length in feet, then add trimming and pattern repeat to each drop.
Formula and assumptions
Drops = ceiling(wall length in feet × 12 ÷ roll width in inches); drops per roll = floor(roll length ÷ (wall height + per-drop allowance)); rolls = ceiling(drops ÷ drops per roll).
Worked example
For 40 ft of wall, 8 ft height, 21 inch wide × 33 ft long rolls and 0.5 ft allowance, the estimate is 8 rolls.
Before you buy
Add the actual pattern repeat, confirm whether the seller states single or double rolls, and keep the same dye lot.
Can I subtract doors and windows?
This calculator does not subtract them because offcuts may not create full matching drops. A detailed hanging plan can reduce the final quantity.
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Editorial review: September 2026. This is a planning estimate; confirm dimensions and product specifications before purchase.