Wallpaper Needed Calculator

Wallpaper is bought by the roll, but the room is measured in square feet. Convert the walls into an area, subtract the openings, then divide by what one roll actually covers.

Room lengthThe length of the room, in feet.Room widthThe width of the room, in feet.Ceiling heightThe height of the walls, in feet.DoorsHow many doors open on to the room.Area of one doorThe area of a single door, in square feet.WindowsHow many windows the room has.Area of one windowThe area of a single window, in square feet.Coverage per rollThe usable area one roll covers, after pattern matching.Price per rollLeave at zero to hide the cost figure.

Wall area to paper

280

Rolls to buy: 10
Gross wall area before openings: 352
Total cost: 400

Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.

The formula this calculator uses

rolls = (2 x (length + width) x ceiling height - openings) / coverage per roll

P: The perimeter of the room, in feet
H: The ceiling height, in feet
O: The total area of the doors and windows
C: The usable area one roll covers

How to check the result by hand

1
Find the perimeter
Add the length and the width and double it. A 12 by 10 foot room has a perimeter of 44 feet.
2
Multiply by the ceiling height
Forty four feet of wall at eight feet tall is 352 square feet of wall before anything is deducted.
3
Subtract the openings
Two doors at 21 square feet and two windows at 15 square feet come to 72 square feet, leaving 352 - 72 = 280.
4
Divide by the coverage of a roll
A roll covering 30 usable square feet means 280 divided by 30, which is 9.33 rolls before rounding.
5
Round up and add a spare
Nine point three three rolls rounds up to 10, and one more is worth holding back for repairs and future damage.

For worked examples, common mistakes and the limits of this formula, read the full How To Calculate Wallpaper Needed page.