Enter the size of the room, the wall height and your roll size. The calculator counts how many full-height strips cover the walls, how many strips you get from each roll, and the number of rolls to buy.
How the wallpaper calculator works
Wallpaper is hung in vertical strips, and offcuts from one roll rarely make a full strip. Counting strips gives a more reliable number than dividing the wall area by the roll area.
- Strip length = wall height + pattern repeat + 4 in for trimming top and bottom.
- Strips per roll = roll length ÷ strip length, rounded down.
- Wall width = room perimeter − 3 ft for each door. Windows are not subtracted, because the wall above and below them is papered.
- Strips = wall width ÷ roll width, rounded up.
- Rolls = strips ÷ strips per roll, plus any extra, rounded up.
Worked example
A 12 × 14 ft room with 8 ft walls and one door has a perimeter of 52 ft, so 49 ft of wall to cover. With 20.5 in × 33 ft rolls, each strip is 96 + 4 = 100 in long and one roll gives 3 strips. 588 in ÷ 20.5 in = 28.7, so you need 29 strips, and 29 ÷ 3 rounds up to 10 rolls.
Rolls per room size
8 ft walls, one door, no pattern repeat, no extra.
| Room size | 20.5 in × 33 ft rolls | 27 in × 27 ft rolls |
|---|---|---|
| 10 × 10 ft | 8 | 6 |
| 10 × 12 ft | 8 | 7 |
| 12 × 12 ft | 9 | 7 |
| 12 × 14 ft | 10 | 8 |
| 14 × 16 ft | 12 | 9 |
| 16 × 20 ft | 14 | 11 |
Step by step: measuring for wallpaper
Tips before you order
- Check that every roll has the same batch or lot number. Color can vary slightly between batches.
- Many US wallpapers are sold as double rolls, about 20.5 in wide and 33 ft long. Check what one “roll” means on the price tag.
- Patterns with a drop match or a large repeat waste more paper. Add 10–15% extra for them.
- Feature walls, ceilings and stairwells are easier to count separately and add up.
