Wallpaper Calculator
How many rolls of wallpaper do you need? Enter the size of the room, the wall height, the number of doors and windows, and the size of your roll to get the number of rolls to buy.
Rolls of wallpaper
10
Check the highlighted fields to see your result.
- Strips needed
- 30
- Strips per roll
- 3
- Wall area
- 363.5 ft²
Results are estimates for information only and do not constitute financial, medical, or legal advice.
How it works
The calculator uses the strip method. It finds how much wall there is around the room, takes off the doors and windows, and divides by the width of the roll to count the strips. Each strip is as tall as the wall, plus 4 in (10 cm) to trim, plus the pattern repeat. From the roll length it works out how many full strips come out of one roll, and then how many rolls you need, adding the extra for waste.
The formulas
Strips = (2 × (length + width) − openings × 1 m) ÷ roll width, rounded up
Strips per roll = roll length ÷ (wall height + trim + repeat), rounded down
Rolls = strips × (1 + extra) ÷ strips per roll, rounded up
Worked example
A room of 14 × 12 ft, walls 8 ft high, 2 doors or windows, rolls of 20.5 in × 33 ft, no repeat, 10% extra.
- Wall around the room: 2 × (14 + 12) = 52 ft, minus about 6.6 ft for the two openings = 45.4 ft.
- Strips: 45.4 ft ÷ 20.5 in = 27 strips. With 10% extra: 30 strips.
- Each strip is 8 ft + 4 in = about 8.3 ft, so a 33 ft roll gives 3 strips.
- Rolls: 30 ÷ 3 = 10 rolls.
Frequently asked questions
How many rolls of wallpaper do I need for a room?
Measure the room and the wall height, then enter the size of your roll. The calculator works out how many strips fit across the walls, how many strips you get from each roll, and the number of rolls. For a 14 × 12 ft room with 8 ft walls and two openings, you need about 10 rolls of 20.5 in wide, 33 ft long.
What is the pattern repeat?
The repeat is the distance before a pattern repeats itself. To match the pattern between strips, each strip is cut longer, so you get fewer strips from each roll. The repeat is printed on the roll label. Leave it at 0 for plain wallpaper or patterns that do not need matching.
Is a single roll or a double roll?
It depends on the store and country. In the US, wallpaper is often sold as a double roll, which is about 33 feet long, even if the price is for a single roll. Check the label for the real length and enter that.
Should I buy extra?
Yes. About 10% extra covers mistakes and later repairs. Buy all rolls from the same batch, because colors can differ slightly between batches.