Wallpaper Calculator Formula

Understand the math behind the wallpaper calculator. Each variable explained with a worked example.

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Formulas Used

Rolls Needed

rolls_needed = ceil(net_area / roll_coverage * 1.10)

Net Wall Area

wall_area = net_area

Area with 10% Waste

waste_area = net_area * 1.10

Variables

VariableDescriptionDefault
room_perimeterRoom Perimeter(ft)52
wall_heightWall Height(ft)9
door_window_sqftDoors & Windows Area(sq ft)40
roll_coverageRoll Coverage(sq ft/roll)56
gross_wall_areaDerived value= room_perimeter * wall_heightcalculated
net_areaDerived value= gross_wall_area - door_window_sqftcalculated

How It Works

How to Calculate Wallpaper Rolls

Measure the room perimeter and wall height to get gross wall area. Subtract doors and windows. Add 10% for waste/pattern matching.

Formula

Net Area = (Perimeter x Height) - Doors/Windows

Rolls = ceil(Net Area x 1.10 / Coverage Per Roll)

Worked Example

52 ft perimeter, 9 ft walls, 40 sq ft doors/windows, 56 sq ft rolls.

room_perimeter = 52wall_height = 9door_window_sqft = 40roll_coverage = 56
  1. 01Gross wall area = 52 x 9 = 468 sq ft
  2. 02Net area = 468 - 40 = 428 sq ft
  3. 03With 10% waste = 428 x 1.10 = 470.8 sq ft
  4. 04Rolls needed = ceil(470.8 / 56) = 9 rolls

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