Wallpaper Calculator
Calculate the number of wallpaper rolls needed for a room, accounting for roll dimensions, door and window deductions, and a 10% installation waste allowance.
Results
What is it?
The Wallpaper Calculator determines how many rolls of wallpaper you need to cover the walls of a room, subtracting door and window openings and adding a 10% overage for seams, pattern matching, and trimming. Enter your roll's actual width and length for accurate results.
How to use
1. Enter room dimensions and wall height. 2. Check the roll packaging for roll width (in inches) and length (in feet). 3. Enter the number of doors and windows. 4. A 10% waste factor is automatically applied.
Example scenario
A 12 × 10 ft room, 9 ft ceilings, 1 door, 2 windows, using rolls that are 21 in wide × 33 ft long: net wall area = 2×22×9 − 21 − 30 = 396 − 51 = 345 ft². Coverage per roll = 33 × (21/12) = 57.75 ft². Rolls = ceil(345/57.75 × 1.1) = ceil(6.57) = 7 rolls.
Pro tip
Always order one extra roll from the same dye lot — different lots can have subtle color variations that become obvious on the wall. If your wallpaper has a pattern repeat, waste increases significantly (add 15–20% for patterns repeating every 18+ inches) — account for this by reducing the effective roll length in your order.