Wallpaper Calculator
Your details
Result
Rolls to buy
- Area to cover
- 365 sq ft
- Including waste
- 419.7 sq ft with 15% waste
- Drops needed
- 30 drops at 1.75 ft wide
- Length to cut each drop
- 8 ft per drop
- Gross wall area
- 416 sq ft (52 ft perimeter × 8 ft)
- Openings deducted
- 51 sq ft for 1 door(s) and 2 window(s)
- US wallpaper is priced by the single roll but almost always sold as a double roll — so a quoted "price per roll" is usually half what you actually pay. Check which unit the price refers to before comparing products.
- With no pattern repeat entered, only the match waste is applied. If the paper has a repeat, enter it — on an 8 ft wall a 21 in repeat adds over 20% to the order on its own.
- Buy all rolls from the same batch or dye lot and check the numbers match on delivery. Colour varies measurably between print runs, and a mid-wall mismatch cannot be fixed without re-hanging.
Rolls by pattern match
The match type and the repeat together decide the waste, which decides the order.
| Match type | Match waste | With repeat | Rolls |
|---|---|---|---|
| Random match | 10% | 10% | 8 |
| Straight match (yours) | 15% | 15% | 8 |
| Half-drop match | 20% | 20% | 8 |
How many rolls of wallpaper do I need?
Multiply the room perimeter by the wall height, deduct doors and windows, add waste for the pattern match, then divide by the roll's usable coverage. A 14 by 12 ft room with 8 ft walls needs 420 square feet, which is 8 double rolls.
area = perimeter × height − openings rolls = ⌈area × (1 + match waste + repeat ÷ height) ÷ roll coverage⌉- perimeter
- 2 × (length + width)
- match waste
- 10% random, 15% straight, 20% half-drop
- repeat ÷ height
- Dead loss at the top of every drop
- roll coverage
- About 56 sq ft usable for a US double roll
Wall area works the same way as it does for paint, but everything after that is different, and the pattern repeat is the reason. A patterned paper has to align horizontally across every seam, which means each drop must start at the same point in the pattern. So a drop is not cut to the wall height — it is cut to the next whole multiple of the repeat above the wall height, and the difference is dead loss at the top of every single drop. On an 8 foot wall a 21 inch repeat means cutting each drop to 8.75 feet, losing 9 inches every time, which adds over 20% to the order before any match waste is counted. The match type then adds its own: a random match needs no alignment at all, a straight match aligns at the same height across seams, and a half-drop offsets every other drop by half a repeat, wasting the most. The other trap is purely commercial. American wallpaper is priced by the single roll but sold almost exclusively as a double roll, so a quoted per-roll price is typically half what you will actually pay.
- Add the room length and width, then double it for the perimeter.
- Multiply the perimeter by the wall height for gross area.
- Deduct 21 sq ft per door and 15 per window.
- Add waste for the match type and the pattern repeat.
- Divide by the roll's usable coverage and round up.
Worked example: A 14 × 12 ft room with 8 ft walls, one door, two windows, straight match, no repeat
A 14 × 12 ft room with 8 ft walls, one door, two windows, straight match, no repeat
The perimeter is 2 × (14 + 12) = 52 ft, so the gross wall area is 52 × 8 = 416 square feet. Deducting 21 for the door and 15 each for the two windows removes 51, leaving 365 square feet to cover. A straight match adds 15%, giving 419.7 square feet, and at 56 square feet usable per US double roll that is 7.5 rolls — so you buy 8. The paper is about 21 inches wide, so the 52 ft perimeter needs 30 drops. Now add a pattern repeat and the arithmetic changes sharply: a 21 inch repeat on an 8 ft wall means cutting each drop to 8.75 ft instead of 8, losing 9 inches at the top of all 30 drops. That pushes the waste from 15% to 37%, the area to 499.6 square feet and the order from 8 rolls to 9. The repeat, not the match, is what drives a wallpaper order.
What each wallpaper input means
- Room length
- Used with the width to work out the perimeter.
- Room width
- The other dimension of the room.
- Wall height
- Floor to ceiling, or to a picture rail if you are papering below it only.
- Roll type
- US wallpaper is priced as a single roll but almost always sold as a double, which is the confusing part. The usable figures here already allow for trimming.
- Pattern match
- A random match can be hung without aligning, so waste is minimal. A half-drop match offsets every other drop and wastes the most.
- Pattern repeat
- The vertical distance before the pattern starts again, printed on the label. A large repeat forces each drop to be cut longer, and the offcut is dead loss.
- Doors
- Each deducts 21 sq ft.
- Windows
- Each deducts 15 sq ft.
What this wallpaper does not account for
- The pattern repeat is the biggest driver of waste, not cutting care. Each drop must be cut to the next whole multiple of the repeat, so the offcut at the top of every drop is dead loss.
- US wallpaper is priced by the single roll but sold as a double. A quoted per-roll price is usually half what you actually pay, which makes cross-product comparison misleading.
- Buy all rolls from the same batch or dye lot and check the numbers on delivery. Colour varies between print runs and a mid-wall mismatch requires re-hanging.
- A half-drop match offsets every other drop by half the repeat, which wastes more than a straight match. A random match needs no alignment and wastes least.
- Deduct openings but keep the waste allowance — offcuts from above a door or window are rarely tall enough to use as a full drop.
- Roll coverage figures here are usable area after trimming. The nominal area printed on a roll is larger and will under-order if used directly.
- Sloping ceilings, stairwells and chimney breasts need each drop measured individually rather than an average height.
- Lining paper, paste and seam adhesive are separate purchases. A heavily textured or damaged wall may need lining before the finish paper goes up.
Frequently asked questions
How many rolls of wallpaper for a 12x14 room?
Eight US double rolls for 8 ft walls with a straight match and no repeat. The room has 416 square feet of wall, 365 after deducting a door and two windows, and 420 with 15% waste.
What is a pattern repeat and why does it matter?
The vertical distance before the pattern starts again. Each drop must be cut to a whole multiple of it, so a 21 inch repeat on an 8 ft wall wastes 9 inches per drop — over 20% of the order.
Is a single roll or double roll standard in the US?
Wallpaper is priced by the single roll but sold almost exclusively as a double. A double roll covers roughly 56 usable square feet, about twice a single.
What is the difference between straight and half-drop match?
A straight match aligns the pattern at the same height across every seam. A half-drop offsets alternate drops by half a repeat, which uses more paper but disguises seams better.
Do I need to subtract windows and doors?
Yes, about 21 square feet per door and 15 per window — but keep the full waste allowance, since offcuts from above an opening are rarely tall enough to serve as a drop.
Why must all rolls come from the same batch?
Because ink colour varies measurably between print runs. A roll from a different dye lot will read as a different shade on the wall, and the only fix is re-hanging.
Sources and review
Last reviewed .