Wallpaper roll calculator for multiple walls and pattern repeats

This wallpaper roll calculator turns your wall heights and widths into a clear roll count. It computes drop length by adding a small trim allowance and, if a pattern repeat is present, rounds the drop length up to the next full repeat so patterns align across seams. It then finds how many full drops you can cut from a roll and how many total drops you need for your room based on the wall widths. The final answer is the number of rolls rounded up, plus a friendly suggestion to keep one spare for repairs and color-batch matching.

For a fast room estimate, add each wall width in your space and enter the overall wall height. Most wallpapers cover standard openings such as doors and windows by trimming around them, so widths are usually not reduced unless large areas of wall will remain unpapered. If your design skips certain spans entirely, simply omit those widths or subtract them from the wall they sit in.

Roll sizes vary by brand and region. The common European roll is 53 cm by 10 m, while in North America 20.5 in by 33 ft and 27 in by 27 ft are popular. Choose a preset or set a custom width and length if your product is different. Pattern repeats can be straight, drop or half-drop; this calculator uses the repeat distance to make sure each cut is long enough to maintain alignment regardless of the match type.

To avoid shade variation, mix or alternate rolls from the same batch number and keep one unopened roll for future touch-ups. If your walls are rough or newly skimmed, a liner paper can improve finish and make removal easier later. Measure twice, cut once, and keep your knife blades fresh to reduce tearing at the seams.

We sum the wall widths to find total width. Drop length equals wall height plus trim allowance; if a pattern repeat is greater than zero, we round the drop length up to the nearest multiple of that repeat. Drops per roll equals floor(roll length ÷ drop length). Drops needed equals sum over each wall of ceil(wall width ÷ roll width). Rolls equals ceil(total drops ÷ drops per roll). Because cuts must be full height, partial drops are not counted. The output includes your drop length, drops per roll, total drops, and the final roll count in the unit you selected.

If drops per roll ends up low due to a large repeat, try using a longer roll or consider changing the trim allowance slightly; both can reduce waste. Always check your manufacturer’s guidance for complex matches or murals, which may require bespoke calculations.