How many rolls of wallpaper do I need?
A standard 12 × 12 ft room needs roughly 16–17 single rolls (about 8 double rolls) of wallpaper. The exact number depends on your wall area, the roll's usable coverage, and how much you lose to pattern matching. Here's how to get it right.
The formula
Rolls = (wall area − openings) × (1 + waste %) ÷ usable coverage per roll
- Wall area = 2 × (length + width) × wall height
- Openings = about 21 sq ft per door and 15 sq ft per window
- Waste = 10–15% for pattern matching (more for large repeats)
A worked example
For a 12 × 12 ft room with 8 ft walls, one door, one window, and single rolls (~25 sq ft usable):
- Wall area: 2 × (12 + 12) × 8 = 384 sq ft
- Subtract openings: 384 − 21 − 15 = 348 sq ft
- Add 15% pattern waste: 348 × 1.15 = 400 sq ft
- Divide by 25: 400 ÷ 25 = 16 → 17 rolls (round up)
Let the calculator handle it
Enter your room size and roll coverage into our wallpaper calculator to get the exact number of rolls — plus the cost — in seconds.
Open the Wallpaper CalculatorSingle vs. double rolls
Wallpaper is priced confusingly: it's often sold as single rolls but packaged as double rolls on one bolt. A double roll holds about twice the paper, which means fewer seams and usually better value. Whichever you buy, use the usable coverage on the label — it's lower than the raw size once trimming is accounted for.
Mind the pattern repeat
Every strip has to line up with its neighbor, so part of each drop is trimmed away. Small or random patterns waste little (about 10%); large repeats can waste 15–20%. When in doubt, round up and keep a spare roll — buying the same batch (lot) number later is rarely possible.