How many rolls of wallpaper do I need for a 12 × 10 ft room with 8 ft walls?
For the worked example (12 × 10 ft room, 8 ft walls, 20½ in × 33 ft rolls, 12 in straight-match repeat, 4 in trim) the material list is Wallpaper rolls: 9 rolls (calculated 26 drops ÷ 3 per roll = 8.67 rolls, based on 20.5 in × 33 ft rolls, 12 in straight-match repeat, 4 in trim). Quantities to buy are whole units rounded up from the calculated amounts. Enter your own measurements in the calculator above for your exact list.
How to use this calculator
- Choose a whole room or a run of wall, and enter the dimensions and the wall height.
- Enter the roll width, roll length and pattern repeat from your paper. Use 0 for no repeat, which also covers a free or random match.
- Optionally add a trim allowance per drop if your instructions give one.
- Copy, print or share the roll count.
How this is calculated
- Wall run = 2 × (room length + room width), or the wall width you enter
- Drop length = wall height + trim, rounded up to a whole pattern repeat if there is one
- Drops = round up (wall run ÷ roll width)
- Drops per roll = round down (roll length ÷ drop length)
- Rolls = round up (drops ÷ drops per roll)
Geometry is deterministic. Material coverage, density, installation waste and product yield can vary. We expose those assumptions so you can replace them with the values printed on the products you are actually buying. Treat every result as an estimate. Items on your list are labelled Calculated (straight from your measurements) or Estimated (depends on an assumption), and “Buy” quantities are whole units rounded up.
Sources
No third-party figure is built into this calculator. Quantities come from geometry and from the values you can see and edit under “Assumptions” below, each labelled by where it comes from.
Last reviewed: . See the methodology.
Assumptions
These starting values are used until you change them. They are typical, not universal. Check the label on the product you are buying.
| Assumption | Starting value | Where it comes from |
|---|---|---|
| Rolls come from drops | Not from area | Mathematical – Wallpaper is cut in full-height drops, so a roll supplies a whole number of them |
| Roll width | You enter it | You enter it (product / supplier) |
| Roll length | You enter it | You enter it (product / supplier) |
| Pattern repeat | 0 in | You enter it (product / supplier) |
| Trim allowance per drop (optional) | You enter it | You enter it (product / supplier) |
Worked example
A 12 × 10 ft room with 8 ft walls and 20½ in × 33 ft rolls with a 12 in straight-match repeat and 4 in of trim:
- Wallpaper rolls: 9 rolls (26 drops, 3 per roll) · 20.5 in × 33 ft rolls, 12 in straight-match repeat, 4 in trim
Common questions
Why not divide wall area by roll area?
Because paper is hung in full-height drops. A roll supplies only a whole number of drops, and a pattern repeat lengthens each drop, so dividing areas can under-count. The drop method counts what you can actually hang.
Are doors and windows subtracted?
No. A drop above a door or below a window is still cut from a full-height piece, so an opening rarely saves a whole drop. Reduce the count yourself only if you know how you will cut.
What about half-drop, offset or random patterns?
Half-drop and offset matches are not modeled: they use more paper than a straight match, so treat this as a minimum and follow your paper’s instructions. A free or random match has no repeat to line up, so enter a pattern repeat of 0.