Wallpaper Calculator
Free wallpaper calculator. Enter wall width, height and pattern repeat to get the number of rolls and strips you need, accounting for doors and windows.
Based on standard 21" wide × 33' long double rolls, using the strip method so the pattern matches at every seam.
Openings reduce the reported wall area only. Roll quantity uses full-height strips across the entire wall; without opening dimensions and positions, it does not assume strips can be saved around doors or windows.
About the Wallpaper Calculator
Estimate full-height strips and rolls using fixed 21-inch-wide, 33-foot-long rolls. The calculation adds one entered pattern repeat to each strip’s height as a waste allowance. Openings are subtracted from the reported wall area, but do not reduce the strip or roll count. This simplified estimate does not model drop matches, individual cut placement or other roll sizes.
Features
- Whole-roll and full-height-strip estimate
- One-repeat allowance per strip
- Net wall area after openings
- Fixed 21-inch by 33-foot roll size
- Metric or imperial measurement inputs
How to use this tool
The Wallpaper Calculator works right in your browser — no signup, no installation. Follow these steps:
- Select units and enter wall width and height.
- Enter the pattern repeat used for the allowance.
- Optionally enter openings to adjust the reported area.
- Review the simplified roll estimate against your actual roll specifications.
Frequently asked questions
How are rolls estimated?
Wall width determines the number of full-width strips. The tool divides roll length by wall height plus one pattern repeat to estimate strips per roll, then rounds the required rolls up.
Do doors and windows reduce the roll count?
No. Openings change the net wall-area figure only. The roll count still uses full-height strips across the whole wall.
Can I change the roll size?
No. This tool assumes 21-inch by 33-foot rolls. Use the manufacturer’s roll dimensions and matching instructions when planning your purchase.
Using the results
The Wallpaper Calculator estimates quantities from your measurements and the stated assumptions. Check dimensions, product coverage and project requirements before buying materials.