Wallpaper Calculator
Enter a room's sizes and the roll's width, length and pattern repeat from its label, and get the strips, the drop length with the repeat counted and the rolls to order, with how many the area method falls short by.
Estimates for planning, not professional advice. Read the full notice.
Example: a twelve by fourteen foot room
11 wallpaper roll
- Strips across the walls 31 strips
- Drop, cut length of one strip 100 in
- Drops from one roll 3 drops
- Rolls by area on the net wall area 7 rolls
- Rolls the area method falls short by 4 rolls
Estimate for planning, from what you entered and the product data shown. Check product labels and your supplier before you buy.
Your project
Enter a size to see your total.
Each product is rounded up once for the whole project, so the total can be less than the items bought alone added together. A line counted from a cut layout (sheets, boards or tiles laid out piece by piece) is counted for each item and added.
Shopping list
| Item | Size | Buy |
|---|---|---|
| Wallpaper | wallpaper roll | 11 |
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Worked example: a twelve by fourteen foot room
Show the working
- Strips: the distance around the room divided by the roll width 624 in ÷ 20.5 in = 30.44 strips
- Round up to whole strips 30.44 strips = 31 strips
- Drop: the wall height plus the trim 96 in + 4 in = 100 in
- Drops from one roll, whole drops only 396 in ÷ 100 in = 3.96 drops
- Rolls: strips divided by the whole drops one roll gives, rounded up once 31 strips ÷ 3 drops = 11 wallpaper rolls
Assumptions
The figures behind the example. Sourced figures link to their source below; a default is a starting value to check against your label or supplier.
| Assumption | Value | Details and changes |
|---|---|---|
| Roll width by length | 20.5 in × 396 in | |
| Default An example roll, not a typical one. Check your label or supplier. | ||
| Pattern repeat | 21 in | |
| Default Printed on the roll label; leave it empty for a pattern with no repeat. Check your label or supplier. | ||
| Trim allowance, top and bottom together | 4 in | |
| Default Our assumption for cutting a drop. Check your label or supplier. | ||
Feet and inches, like 12' 6"
The example room at four pattern repeats
Drop length and rolls for the example room at four pattern repeats, with a straight match and with a half-drop
| Pattern repeat | Drop length | Rolls, straight or random match | Rolls, half-drop match |
|---|---|---|---|
| No repeat | 100 in | 11 rolls | 11 rolls |
| 12 in repeat | 108 in | 11 rolls | 11 rolls |
| 21 in repeat | 105 in | 11 rolls | 11 rolls |
| 24 in repeat | 120 in | 11 rolls | 11 rolls |
The repeats are examples; yours is printed on the roll label. A half-drop makes every strip after the first longer by half the repeat. A pattern with no repeat gives the same rolls for both.
Questions
How many rolls of wallpaper do I need for a twelve by twelve room?
Enter the room's length, width and wall height and the roll's size from its label. The calculator counts strips across the walls, cuts each drop to the height plus the trim and the repeat, and rounds the rolls up once.
What is a pattern repeat?
It is the distance down the roll before the pattern starts again, printed on the label. Each drop is cut to a whole number of repeats so neighbouring strips line up, which is why a repeat can add a roll.
Why not just divide the wall area by the roll area?
Strips are cut whole from the roll, and each drop has trim and repeat waste at the top, so rolls hold fewer strips than their area suggests. The example shows how many rolls the area method falls short by.
Single roll or double roll?
A double roll is two single rolls sold together. Choose how your roll is sold and the order is rounded up in that unit, so an odd count of single rolls buys one more.