Wallpaper is sold by the roll, but rooms are covered strip by strip, and pattern matching eats into every roll. This calculator counts the strips your walls need, works out how many full strips each roll gives you after matching the pattern, and turns that into the number of rolls to buy.
Wallpaper Calculator
Find out how many rolls you need, with pattern repeats and drop matches taken into account.
Assumptions: each strip is rounded up to a whole pattern repeat so the pattern lines up, then 4 in is added for trimming at the top and bottom. For half drop matches, the cutting length is estimated as the strip length plus half a repeat, which averages out the alternating strips. Doors and windows are not subtracted, because the offcuts are usually needed around them. Buy all rolls from the same batch number.
How it works
- Choose whether you are papering a whole room or a single wall, then enter the measurements.
- Pick your roll size, US double, US single or European, or enter a custom roll.
- Add the pattern repeat from the roll label, and choose a straight match or a half drop match.
- The result shows strips needed, the cutting length per strip, strips per roll, and rolls to buy.
Frequently asked questions
What is a pattern repeat?
It is the distance down the roll before the pattern starts again, printed on the label. Each new strip has to begin at the right point in the pattern so it lines up with its neighbour, and that is why longer repeats use more paper.
What is the difference between a straight match and a half drop?
With a straight match, the pattern lines up at the same height on every strip. With a half drop, alternate strips are shifted by half a repeat, which looks softer but needs a little more length per pair of strips.
Should I subtract doors and windows?
Usually not. The paper you lose matching patterns and trimming around openings roughly equals the area of the doors and windows, so papering the full wall measurement is the safer estimate.