Wallpaper Calculator

About this calculator

Estimating wallpaper needs starts with the wall's area, but the real number of rolls depends on how the roll's dimensions divide into usable strips: a standard roll is cut into vertical strips the height of the wall, and each strip needs a trim allowance — commonly around 10 cm — to account for pattern matching and cutting waste at the ceiling and floor edges. Dividing the wall's width by the strip's usable width gives the number of strips needed, and dividing the roll's length by the trimmed strip height gives strips per roll.

Decorators, DIY renovators and paint-and-paper retailers use this kind of calculation to avoid the two common failure modes of a wallpapering job: running out of rolls partway through a wall, which risks buying a later batch with a slightly different dye lot, or over-ordering and paying for rolls that end up as waste. Getting the roll count right before the project starts is standard practice on any quote or shopping list for a wallpapering job.

Enter your wall's dimensions and the size of the roll you plan to use, and the calculator returns the number of rolls to buy, trim allowance included.