How Many Rolls of Wallpaper Do You Need
A plain guide to sizing wallpaper: measuring the wall, reading roll labels, handling pattern repeats and turning strips into rolls to buy.
Measure the wall the way the tool expects
Start with a single flat wall and measure its width from corner to corner and its height from skirting to ceiling. Take the tape reading at a couple of points and use the larger figure, since walls are rarely perfectly square. Keep both numbers in one unit, either feet or meters, and enter them as the wall width and wall height. If you are papering a whole room, size each wall on its own and total the rolls at the end.
Read the roll label correctly
Every wallpaper roll lists two dimensions: the width of the paper and the total length wound on the roll. A common British and European roll is about 0.53 m wide and 10 m long, while many American rolls run near 1.75 ft wide. The width decides how many strips it takes to span the wall, and the length decides how many full drops you can cut from a single roll. Enter both exactly as printed so the strip maths lines up with reality.
Why pattern repeat changes everything
A plain paper lets you cut one drop straight after another, so a 10 m roll of 2.4 m drops gives four strips. Add a 0.64 m repeat and each usable drop effectively becomes about 3.04 m, so the same roll now yields only three strips and you waste the offcut needed to realign the design. That is why a bold patterned paper can push the roll count up by a quarter or more compared with a plain one. Random match papers avoid the penalty because any drop meets any neighbour, so you can set the repeat to zero.
From strips to rolls to a shopping list
The calculator divides the wall width by the roll width and rounds up to get the strips needed to cover the wall. It divides the roll length by the strip length, which is the wall height plus the repeat, and rounds down to get strips per roll. Dividing one by the other and rounding up gives the rolls to buy. Because each step rounds in the safe direction, the figure already leans slightly generous, but a single spare roll from the same batch still protects you against miscuts and later repairs.