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Wallpaper Calculator

Enter your walls and roll size to get the number of rolls — counted the way decorators actually do it, by full-height strips rather than square feet.

Where are you?

AWG, NEC, 120/240 V, miles and gallons — we remember this on every calculator.

Your walls

Tick each wall you are papering and enter its width. Measure the wall itself, not the room, and add rows for as many walls as you need.

Wall height

Floor to ceiling. Measure in a few places — old houses are rarely consistent, and you cut to the tallest.

Roll size

US wallpaper is priced by the single roll but almost always sold in double-roll bolts. European rolls are 53 cm by 10 m.

Pattern repeat

Printed on the roll label as the vertical repeat. Set 0 for a plain, textured or random-match paper — this is where the waste comes from.

Full-height doorways

Only count openings that run floor to ceiling, like doors and arches. Windows do not reduce the roll count.

Fine tuning

Extra at the top and bottom of each drop for trimming to the ceiling and skirting. Four inches total is standard.

Your result

US double roll rolls to buy

4 rolls

Strips needed
12
Strips per roll
3
Cut length per strip
100 in
Wall width papered
19 ft
Estimated offcut
27.3%
Pattern repeat
None

🪿 The goose says: Buy 4 rolls. You need 12 strips and each roll gives you 3 — order them all together and check the batch numbers match.

  • Buy every roll in one order and check the batch number on each label. Two batches of the same paper are visibly different in colour, and the join will show for as long as the paper is up.
  • About 27.3% of the paper you buy will be offcut, because your 0 in repeat forces each drop up to a whole pattern. Large repeats are where wallpaper budgets go wrong.
  • Windows are deliberately not deducted. The paper above and below a window still has to be cut from a full-height drop, so treating a window as a saving is how people end up a roll short.

How this wallpaper calculator works

Almost every online wallpaper calculator divides wall area by roll area, and almost every one of them gives you the wrong answer. Wallpaper is not spread over a wall like paint — it is hung in full-height strips, and a strip that is two inches too short is worthless.

The method decorators actually use counts strips. Work out how many drops fit across your wall width at the roll width, work out how many drops you can cut from one roll at your drop length, and divide. Everything else is detail.

The pattern repeat is what makes it expensive. With a straight match every drop must begin at the same point in the pattern, so an 8 foot wall with a 21 inch repeat needs a drop cut at 105 inches rather than 100 — and the leftover is usually too short to use.

  1. Step 1 Total wall width width = Σ wall widths − full-height doorways Windows are not deducted: the paper above and below still comes off a full drop.
  2. Step 2 Cut length per strip strip = wall_height + trim_allowance, rounded up to a whole repeat Trim allowance is 4 in total, two at each end.
  3. Step 3 How many strips you need strips = ceil(wall_width ÷ roll_width)
  4. Step 4 How many strips a roll gives per_roll = floor(roll_length ÷ strip_length) Floor, not round — a partial drop is not a drop.
  5. Step 5 Rolls to buy rolls = ceil(strips ÷ per_roll)

Example: two walls totalling 22 ft, 8 ft high, plain paper, US double rolls at 20.5 in × 33 ft. That is 264 inches of wall, needing 13 strips of 100 inches. Each 396-inch roll gives 3 strips, so you need 5 rolls.

Assumptions & caveats

Everything this calculator quietly assumes on your behalf. If one of these does not match your situation, the answer will be off.

  • The strip method is used rather than area division, because wallpaper is hung in full-height drops and offcuts shorter than the wall are almost never usable. Area-based estimates typically come out one to two rolls short.
  • Full-height doorways are deducted from wall width; windows are not. Paper above and below a window still has to be cut from a whole drop, so counting a window as saved area is the single most common mistake.
  • A straight pattern match is assumed. Offset or drop-match patterns alternate the starting point between strips, which nests better and wastes slightly less — this calculator will slightly over-order for those.
  • Trim allowance defaults to 4 inches per strip, two at the top and two at the bottom. Rooms with badly out-of-level ceilings need more.
  • Roll dimensions are the common nominal sizes. US rolls are priced as singles but almost always sold in double-roll bolts; European rolls are 53 cm by 10 m. Check your specific paper, since designer rolls vary.
  • No allowance is made for feature walls with tricky cut-ins, alcoves, chimney breasts or staircases. Anything with an angled cut needs extra.
  • Peel-and-stick papers are calculated the same way, but they are more forgiving of a short drop because panels can be overlapped slightly at the seam.

Frequently asked questions

How many rolls of wallpaper do I need for a room?

For a typical 12 × 10 ft room with 8 ft ceilings and one door, plain paper needs about 8 to 9 US double rolls to cover all four walls. A single feature wall of 12 ft needs 3. Pattern repeat can push either figure up by 20 to 40 percent.

What does pattern repeat mean on wallpaper?

It is the vertical distance before the design starts again, printed on the roll label. Every strip has to begin at the same point in the pattern for the seams to match, so each drop is cut up to a whole repeat longer than the wall — which is where the offcut waste comes from. A 21-inch repeat on an 8-foot wall wastes about five inches per strip.

Do I subtract windows when calculating wallpaper?

No, and this is the mistake that leaves people a roll short. The paper above and below a window still has to be cut from a full-height drop, and the offcut from the middle is rarely long enough to use elsewhere. Only full-height openings like doors and arches reduce the count.

What is the difference between a single and double roll?

In the US, wallpaper is priced by the single roll of about 27 square feet but manufactured and sold as a double-roll bolt of roughly 56 square feet. You order double rolls; the price you see is often for a single. European rolls are a single standard size, 53 cm wide by 10 m long.

How much extra wallpaper should I buy?

Buy one extra roll beyond the calculation, and buy it at the same time. The extra covers a mis-cut and any future repair, and buying it later means a different batch number and a visible colour difference. Most suppliers will accept returns of unopened rolls.

Why do batch numbers matter?

Wallpaper is printed in production runs and the ink shifts slightly between them. Two rolls from different batches look identical in the shop and obviously different once hung side by side in daylight. Check the batch or dye-lot number on every roll label before you start.

Is peel-and-stick wallpaper measured the same way?

Yes, by strips, but the roll dimensions are different — usually 24 inches wide by about 16 feet. Peel-and-stick is more forgiving because you can reposition it and overlap seams slightly, and most brands are random or straight match with modest repeats.

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