How Many Rolls of Wallpaper Do I Need? (Calculator)
Quick answer: wall area − openings, then divide by roll coverage (a standard roll covers about 25 sq ft) and round up for pattern repeat. A 10×12 room needs about 8–9 rolls. Here's the full method.
- Wallpaper roll math
- Roll sizes
- Worked example
- Pattern repeat
- Ordering tips
- Common mistakes
Wallpaper roll math
Wallpaper is sold in rolls that cover a set area. The plan:
Wall area (sq ft) − openings ÷ roll coverage = rolls, rounded up. Add allowance for pattern matching (see below).
Start by measuring the height of each wall and the full width of the room. Multiply the wall height by the total wall width to get gross wall area, then subtract doors and windows (measure each opening and subtract its exact area — an 80×32 in door is about 18 sq ft).
Roll sizes
| Roll | Coverage |
|---|---|
| Standard roll | ~25 sq ft (usable) |
| Double roll | ~50–55 sq ft |
Usable coverage is less than the labeled area because of trim waste. Most brands quote the "double roll" coverage on the label. The usable figure already accounts for the standard trim you lose at the top and bottom of each strip, so use it rather than the raw roll area when you divide.
Worked example
For a 10×12 room with an 8 ft ceiling:
- Wall area = (10+12)×2 × 8 = 352 sq ft
- Subtract a door + window ≈ 36 sq ft → net 316 sq ft
- Rolls = 316 ÷ 25 = 12.6 → 13 standard rolls, or ~7 double rolls
Pattern repeat
If the pattern repeats, you lose length between strips as you match them — the larger the repeat, the more waste. For a repeat over ~18 in, add 1–2 extra rolls. Large florals and geometric patterns need the most allowance.
The reason: each strip must start at the same point in the pattern to line up across the seam, so a strip cut for a long wall wastes the leftover before the next repeat. Patterns with a repeat of 24 in or more can push waste well above 20%, which is why matching wallpaper is genuinely more expensive than plain.
Ordering tips
Buy all rolls in one batch — dye lots and pattern batches differ, and wallpaper can't be color-matched later. Buy one extra roll and return it unopened if you don't use it. Prepare the wall (clean, dry, smooth) before you order.
Keep the unopened extra roll in its original wrapper for returns, and note the pattern name and batch number on the invoice — you'll need them if you ever have to match a damaged strip later.
Common mistakes
- Ignoring pattern repeat. It adds real waste beyond the area math.
- Using labeled not usable coverage. Trim waste cuts into each roll.
- Forgetting openings. Subtract doors and windows.
- Buying across batches. Shade differences are visible once hung.
- Not rounding up. A partial roll can't be special-ordered mid-hang.
FAQ
Measure wall area minus doors and windows, then divide by about 25 sq ft per standard roll. A 10×12 room with an 8 ft ceiling needs about 13 standard rolls.
A standard roll covers about 25 usable square feet after trim waste. A double roll covers about 50–55 square feet.
Yes. A larger pattern repeat wastes more length matching strips, so add 1–2 extra rolls for repeats over about 18 inches.
No reliably. Dye lots and pattern batches differ, so buy all your wallpaper at once and keep the unopened roll for returns.