Wallpaper Calculator

Wallpaper is bought in rolls, but a roll is a strip of fixed length and width, not a rectangle of wallpaper you can cut freely. That single fact explains why wallpaper estimates always seem to ask for more rolls than the wall area suggests: offcuts at the top and bottom of each drop, and the repeat of the pattern, waste material that cannot be used. Pattern repeat is the biggest source of waste. A plain paper can be hung almost without loss, but a large repeating pattern forces you to line up each drop, cutting away part of every strip to match its neighbour. The bigger the repeat and the shorter the roll, the more is thrown away — an allowance of ten to twenty per cent is typical, higher for a bold, widely spaced design. Drops are what really decide the count. You hang full-height strips from ceiling to floor, so the number of drops is the wall width divided by the roll width, rounded up, and each drop must be at least as long as the wall height plus the pattern offset. Calculating rolls from area alone is a reasonable approximation; calculating them from drop count is exact, which is why paper hangers measure the room, not the paint tin. This calculator takes your wall area, the coverage printed on the roll and a waste allowance for the pattern, then rounds up to whole rolls. It ignores doors and windows, which waste a little more, and assumes a standard roll. Measure the full wall run in a room, buy one extra roll if your pattern is bold, and keep the receipt in case you need a matching batch later.

This calculator returns estimates for planning and general information only. It is not engineering, architectural, structural, electrical or code advice, and it cannot replace a qualified professional who has seen the site. Material quantities depend on the actual dimensions, the product you buy and local building codes, so confirm the figures before ordering materials or starting work, and always follow local regulations.