Wallpaper Calculator
Enter your room's wall perimeter and height, plus your roll's dimensions, to find how many rolls to buy.
How wallpaper quantity is calculated
Wall area is the total perimeter of the room's walls multiplied by the wall height (add up all four walls' lengths to get the perimeter, or subtract door/window areas for more precision). Each roll's area is its width × length.
Dividing wall area by roll area gives the exact number of rolls needed with zero waste. In practice, pattern matching and trimming waste some wallpaper, so a waste allowance (commonly 10%, more for large pattern repeats) is added before rounding up to a whole number of rolls.
Frequently asked questions
How do I find my wall perimeter?
Add up the lengths of all the walls you're papering. For a standard rectangular room covering all four walls, that's 2 × (room length + room width).
Why do I need extra waste allowance for patterned wallpaper?
Patterned rolls need to be matched up at the seams, which means cutting off and discarding some length from each new strip to align the pattern — the larger the pattern repeat, the more waste this typically creates.
What's a standard wallpaper roll size?
A common European roll size is 53 cm wide by 10 m long, though sizes vary by manufacturer and country — always check your specific roll's dimensions.