Wallpaper Calculator
Rolls = (wall area − 21 ft² per door − 15 ft² per window) ÷ usable yield per roll. A 12 × 12 ft room 8 ft high with 1 door and 1 window is 348 ft²: 7 rolls at a 0–6 in repeat. Over a 23 in repeat, Graham & Brown gives no yield: type the one printed on the roll label.
Rolls to buy
7 rolls
348 ft² ÷ 50 ft² usable per roll (0 to 6 in repeat)
- Wall area to cover
- 348 ft² (32.33 m²)
- Walls before openings
- 384 ft²
The repeat yields are Graham & Brown's, for its own rolls: for another brand, choose the label yield.
Check that every roll carries the same batch number.
Worked example
A 12 × 12 ft room, 8 ft high, one door, one window
- Distance around: 12 + 12 + 12 + 12 = 48 ft; 48 × 8 = 384 ft²
- 384 − 21 − 15 = 348 ft²
- Repeat 0 to 6 in: 348 ÷ 50 = 6.96, so 7 rolls
- Repeat 13 to 18 in: 348 ÷ 40 = 8.7, so 9 rolls
Result: 7 rolls, or 9 rolls with a 13 to 18 in repeat.
Checked by the automated test “wallpaper — 12 × 12 ft room, 8 ft high, 1 door, 1 window → 348 ft²: 7 rolls with a 0-6 in repeat, 9 with 13-18 in”.
How it works
Wall area = distance around the room × wall height − 21 ft² per door − 15 ft² per window
Rolls = wall area ÷ usable yield per roll, rounded up
Usable yield per roll by repeat: 0 to 6 in 50 ft², 7 to 12 in 44 ft², 13 to 18 in 40 ft², 19 to 23 in 36 ft²
Assumptions
- Graham & Brown's method and yields, for its own rolls. For another brand, or a repeat over 23 in, use the usable yield printed on the label: the calculator does not extrapolate.
- Doors and windows come off at Graham & Brown's fixed 21 and 15 ft², whatever their size.
Reference table
| Wall area | Repeat 0 to 6 in | 7 to 12 in | 13 to 18 in |
|---|---|---|---|
| 200 ft² | 4 | 5 | 5 |
| 300 ft² | 6 | 7 | 8 |
| 400 ft² | 8 | 10 | 10 |
| 500 ft² | 10 | 12 | 13 |
Wall area after doors and windows. At 19 to 23 in (36 ft² per roll), divide by 36 and round up.
Before you buy
- Walls with a slope or a stair. Enter each awkward wall at its full height: the offcut is part of the cost.
- Solids and stripes. They list no repeat: Graham & Brown counts them at 0, the 0 to 6 in row.
- Order all rolls at once, so they share one batch number (Graham & Brown).
Common mistakes
- Ignoring the pattern repeat The repeat is the vertical distance before the pattern comes back (Graham & Brown): at 13 to 18 in a roll yields 40 ft² instead of 50, 9 rolls instead of 7 here.
- Using one brand's yield for another These yields are Graham & Brown's for its rolls: for another brand, take the usable yield printed on its label.
- Rolls from two batches Graham & Brown asks you to check the batch number on all rolls so the colors match once hung.
- No length left for trimming York Wallcoverings adds about 4 in to each strip, roughly 2 in at the ceiling and 2 in at the baseboard, for trimming, on top of the repeat.
Frequently asked questions
How do I measure for wallpaper?
Measure the width of each wall and the height from baseboard to ceiling, doors and windows included, and multiply. Graham & Brown then takes off 21 ft² per door and 15 ft² per window, and reads the repeat on the label.
How much wallpaper do I need?
Divide the wall area by the usable yield of one roll for its repeat. 348 ft² takes 7 rolls up to a 6 in repeat (50 ft² per roll), 8 rolls at 7 to 12 in, 9 at 13 to 18 in and 10 at 19 to 23 in.
How much wallpaper do I need for a 12x12 room?
With 8 ft walls, one door and one window: 384 − 21 − 15 = 348 ft², so 7 rolls for a repeat up to 6 in and 9 rolls for a 13 to 18 in repeat.
Sources
Formula, examples and sources checked on by the Yardstick Math team. How we check our formulas.
- Wallpaper guide: how to calculate the number of rolls (21 ft² per door, 15 ft² per window, usable yield by repeat) — Graham & Brown (The Home Depot), accessed
- Wallpaper FAQ: what is pattern repeat — Graham & Brown, accessed
- Wallpaper calculator and hanging steps (trim allowance, pattern repeat and match) — York Wallcoverings