THE BASICS
1. Measuring the wall
Multiply total wall width by height: a 12 ft wall with 8 ft ceilings is 96 sq ft. Papering a whole room? Add all four walls and subtract doors (~20 sq ft each) and windows (~15 sq ft each).
Measure at the floor and at the ceiling: walls are rarely square, and baseboards or crown you plan to paper count too.
FIGURES
2. What a standard roll covers
In the US, wallpaper is priced per single roll but sold as double rolls (a bolt): typically 20.5 in wide × 33 ft long, about 56 sq ft of paper with roughly 50 sq ft usable after trimming.
If your paper is 27 in wide or a different bolt length, the math changes — check the product page and use our wallpaper calculator with the exact roll dimensions.
| Wall area | Double rolls (plain) | With large repeat (+1 per 2) |
|---|---|---|
| 50 sq ft | 1-2 rolls | 2 rolls |
| 100 sq ft | 3 rolls | 4 rolls |
| 200 sq ft | 5 rolls | 6 rolls |
| 320 sq ft (10×10 room) | 8 rolls | 10 rolls |
Math with 50 usable sq ft per double roll and 10% strip waste. The pattern repeat adds rolls.
CRITERIA
3. The pattern repeat eats material
The repeat is the vertical distance at which the pattern starts over. On plain (no-repeat) paper, each strip is cut exactly at wall height. With a pattern, every strip must be cut to the next multiple of the repeat so the design matches: an 8 ft wall with a 25 in repeat forces strips of 100 in.
That adjustment wastes 10-30% of the roll depending on repeat size. Rule of thumb: small repeat (under 12 in), add one roll for every four; large repeat (over 20 in), add one for every two.
SHOPPING
4. How many rolls to buy: the formula
Area with waste divided by usable coverage per double roll: (area × 1.1) ÷ 50 for plain paper, rounded up. A 100 sq ft accent wall with plain paper takes (100 × 1.1) ÷ 50 = 2.2 → 3 double rolls; with a big repeat, 4.
Order all rolls from the same dye lot (printed on the label) and keep one spare: reordering months later almost never matches the original tone.
Ready to skip the math?
Calculate rolls for my wall