Wallpaper Calculator
Calculate wallpaper rolls and strips for a room, allowing for pattern repeat and trimming.
What you need
10
Rolls needed — Order all rolls in one go — dye lots vary between production runs.
- Wall area (openings removed)
- 417.0 sq ft
- Area including repeat and waste allowance
- 504.6 sq ft
- Strips to cut
- 31
- Room perimeter
- 52.0 ft
Full-height drops needed to go around the room.
Estimates for planning. Confirm quantities with your supplier before ordering — see the assumptions below for the figures used.
How to use the wallpaper calculator
Wallpaper is bought by the roll but hung in strips, and the pattern repeat decides how much of each roll you actually use. This calculator works out both the roll count and the number of strips, so you can check the two against each other before ordering.
What this calculator assumes
Every estimate depends on figures that vary by supplier and conditions. These are the ones used here, so you can sanity-check the result against your own quote.
- Roll coverage is nominal. Usable coverage is always lower than the printed figure once you match a pattern, which is what the repeat allowance covers.
- Doors are subtracted at 21 sq ft and windows at 15 sq ft each.
- The strip count assumes full-height drops with no horizontal seams and ignores that you can often get a short piece over a door or window out of an offcut.
- Dye lots vary between production runs, so order everything at once and keep a spare roll for repairs.
Frequently asked questions
How many rolls of wallpaper do I need?
Take your wall area after subtracting doors and windows, add 10 to 25% depending on the pattern repeat, then divide by the roll's coverage. A typical 12 by 14 foot room with 9 foot ceilings and a small repeat needs about 8 to 9 US double rolls.
Why does pattern repeat waste wallpaper?
Every strip has to line up with the one beside it, so you cut away part of each drop to get the pattern into position. With a 24 inch repeat you can lose up to two feet per strip. That is why a large repeat carries a 20 to 25% allowance and a plain paper carries none.
What is the difference between a single and a double roll?
American wallpaper is priced by the single roll but almost always packaged and shipped as a double — one continuous bolt of about 56 square feet. Double rolls waste less because you get more full-height strips out of one bolt.
Should I order extra wallpaper?
Yes, one spare roll beyond the calculation. Dye lots shift between production runs, so a roll bought six months later will not match. A spare also covers the strip you inevitably cut short.
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