Wallpaper Calculator: How Many Rolls Do I Need?
Enter your room size, wall height and the pattern repeat. We count the drops you will hang and how many fit on each roll, the way decorators do.
Your estimate
Buy 10 double rolls
28 drops · 3 per roll
- Wall width to cover
- 47.5 ft
- Openings subtracted
- − 36 sq ft1 door, 1 window
- Drop length
- 100 in
- Drops
- 28 (3 per roll)
- Waste
- 48%
Add a price per roll to see the cost.
How we got this: Each drop is 100 in (wall height + trim). One roll gives 3 drops. 28 drops ÷ 3 = 10 rolls.
Check that every roll has the same batch (lot) number. A roll bought later may not match, so add a spare if the pattern is hard to find.
How the calculation works
- Drops. The wall width around the room, minus the width your doors and windows take up, divided by the roll width and rounded up. A door or window counts in proportion to its height: a 3 ft wide window that is 5 ft tall on an 8 ft wall saves about 1.9 ft of paper width.
- Drop length. Wall height plus 4 in (10 cm) for trimming, rounded up to a whole pattern repeat. Half-drop patterns add half a repeat.
- Drops per roll. Roll length ÷ drop length, rounded down. The rest of the roll is offcut.
- Rolls. Drops ÷ drops per roll, rounded up.
Imperial example: a 12 × 14 ft room with 8 ft walls and one door needs 29 drops of 20.5 in paper. With a 21 in repeat each drop is 105 in, so a 33 ft double roll gives 3 drops: buy 10 double rolls.
Metric example: a 4 × 5 m room with 2.5 m walls and one door needs 33 drops of 53 cm paper. With a 53 cm repeat each drop is 2.65 m, so a 10.05 m roll gives 3 drops: buy 11 rolls.
Guides to save and share
Chart as a table: How many rolls of wallpaper do I need?
| Room | 8 ft walls | 9 ft walls | 10 ft walls |
|---|---|---|---|
| 10 × 10 ft (small bedroom) | 7 | 8 | 8 |
| 12 × 12 ft (bedroom) | 9 | 9 | 9 |
| 12 × 14 ft (main bedroom) | 10 | 10 | 10 |
| 14 × 16 ft (living room) | 11 | 11 | 12 |
| 16 × 20 ft (large room) | 14 | 14 | 14 |
How much waste is normal with wallpaper?
| Pattern | Typical extra | Why |
|---|---|---|
| Plain or random match | 10–20% | Only the trim at the top and bottom of each drop. |
| Repeat up to 21 in (53 cm) | 20–35% | Each drop is rounded up to a whole repeat. |
| Repeat over 25 in (64 cm) | 35–50% | Large offcuts at the end of every roll. |
Common mistakes
- Working from wall area instead of drops. Area hides the paper lost to the pattern repeat.
- Ignoring a half-drop match. Every other drop needs extra length.
- Ordering more rolls later. A different batch can be a slightly different shade.
- Cutting drops to the exact wall height with no allowance for trimming.
What else you'll need
- Wallpaper paste, unless the paper is pre-pasted.
- Wallpaper primer or size on new or patched walls.
- A smoothing brush or plastic smoother and a seam roller.
- A utility knife with plenty of spare blades and a straightedge.
- A plumb line or laser level for the first drop.
Frequently asked questions
How many rolls of wallpaper do I need for a 12×12 room?
With 8 ft walls, one door and plain paper, a 12 × 12 ft room needs 27 drops of 20.5 in paper. A 33 ft double roll gives 3 drops of 100 in, so buy 9 double rolls. A pattern repeat can add a roll or two.
What is a pattern repeat?
It is the distance before the pattern starts again, printed on the label. Every drop has to start at the same point in the pattern, so each drop is rounded up to a whole repeat.
What is the difference between a single and a double roll?
In the US, wallpaper is often priced per single roll but sold in double rolls of about 20.5 in × 33 ft (56 sq ft). European rolls are 0.53 × 10.05 m (about 5.3 m²).
Should I subtract windows and doors?
Yes, by their size. We take off the wall width they cover in proportion to their height, because the short pieces above a door and above and below a window can be cut from offcuts. For very small windows the saving is tiny.
Straight match or half-drop: which uses more paper?
Half-drop. The pattern on every other drop sits half a repeat lower, so each drop needs about half a repeat of extra length.
Related calculators
This is an estimate. Actual use depends on the material, the surface, the installation method, waste and site conditions. Check quantities with your supplier before you buy.