Wallpaper Calculator
Work out how many rolls of wallpaper a room needs, allowing for roll size and pattern repeat.
Results are estimates for planning. Roll sizes and pattern repeats vary by brand — always check the label and buy a spare roll from the same batch.
How to Measure for Wallpaper
Wallpaper is hung in vertical strips, so the estimate is built from the room perimeter and the wall height.
Room size
Measure the room length, width, and wall height in feet. The perimeter sets how many strips are needed; the height sets how long each strip must be.
Roll size and repeat
Enter the roll width and length from the label, plus the pattern repeat. A larger repeat trims more from each strip and pushes the roll count up.
Common Mistakes to Avoid
- Ignoring the pattern repeat. A big repeat can waste a foot or more per strip — it materially changes how many rolls you need.
- Mixing batches. Rolls from different batches can vary in color. Buy all rolls together and check the batch number.
- Cutting it too close. Always buy at least one spare roll for mistakes and future repairs.
- Reusing door and window offcuts. Short strips rarely fit elsewhere — don't count on them.
Frequently Asked Questions
Divide the room perimeter by the roll width for the number of strips, see how many strips fit a roll, then divide and round up.
The vertical distance before the design repeats. A larger repeat means more paper is trimmed to line up the pattern.
Safer not to — offcuts around openings rarely reuse, so a solid wall estimate builds in an allowance.
At least one extra roll, all from the same batch number so the color matches.
A common US double roll is about 20.5 in wide and 33 ft long, but sizes vary — check the label.