Free Online Wallpaper Roll Calculator
Calculate wallpaper rolls needed for a room.
Room
Roll
Doors and windows
Calculation detail
The estimate assumes standard straight walls and subtracts the full width of each door and window from the strip count. Buy at least one extra roll when the pattern is large, the walls are uneven, or the batch may sell out, so a future repair can match.
About the Wallpaper Roll Calculator
Wallpaper is sold in rolls, but rooms are measured in walls, doors, windows, and pattern repeats. The mismatch is why so many projects end with one roll too few. This calculator works in strips rather than raw area: it divides the total wall width by the roll width, works out how many full strips fit in a roll after pattern matching, and then adds a waste allowance. The result is a practical roll count and a cost estimate rather than an abstract square-meter figure.
Why strips are more accurate than area
A simple area calculation divides the wall area by the roll area, which ignores the fact that wallpaper is hung in vertical strips. If the wall height is 2.5 meters and the roll is 10 meters long, you can cut four strips of 2.5 meters but not five, and the leftover half-meter is wasted. Pattern repeats make this worse: every strip must be cut at a length that aligns the design, so the usable length per roll drops. The strip method captures both effects and gives a more realistic number.
Doors, windows, and waste
Openings reduce the number of full-width strips needed, but they rarely eliminate a whole strip. The calculator subtracts the width of each door and window from the total wall width, which is a reasonable approximation for openings that run through the wall height. It then adds the waste percentage you choose to cover cutting errors, corners, and future repairs. Ten percent is a common default; large patterns, textured paper, and rooms with many corners may need fifteen or twenty percent.
Measuring tips
Measure each wall separately and add the lengths rather than assuming a perfect rectangle. Use the tallest point of the wall for the height, especially under sloped ceilings. Note the pattern repeat from the roll label and check whether the pattern is straight across or half-drop, because half-drop repeats need more matching allowance. Keep the batch number from every roll, and buy the extra roll at the same time. Changing the unit selector converts the length fields automatically, so double-check any value you typed by hand after a switch.
Frequently asked questions
Should I subtract doors and windows?
Subtract their width from the strip count, as this calculator does, but do not subtract the full area unless the opening spans floor to ceiling. You still need paper above and below most windows, and a door opening usually still requires a strip beside it.
What is a pattern repeat?
The repeat is the vertical distance before the design starts again. A 32 cm repeat means each strip must be cut to a length that is a multiple of 32 cm, so the pattern aligns across seams. Larger repeats produce more waste.
Why does the calculator convert units automatically?
The unit selector changes the length fields between meters and feet so the numbers stay equivalent. The price per roll is not converted because it is a currency amount, not a length. Round values after conversion if you prefer tidy numbers, then confirm the estimate.