Wallpaper calculator.
Count the drops. The rolls follow.
Wallpaper is bought by the roll but hung by the drop, and a drop is cut to the pattern, not to the wall. This calculator lays every drop on your wall, cuts it to whole repeats with a trim allowance, shortens only the drops a door or window clears, and places each cut on a numbered roll. The area method is printed beside it.
02 / Drops on the wall
03 / Rolls to open
- Drops
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- Longest cut
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- Drops per roll
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- Cut total
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- Repeat waste
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- Trim
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- Roll tails
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- Bought for laid
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- Area method
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- Wall area
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Area method is wall area plus 10 percent divided by roll area, the arithmetic most estimators use. The drawn order is the one to buy.
Three match types on the same wall
| Match | Rolls | Longest cut | Cut total | Repeat waste | Yards |
|---|
Roll sheet
Every drop and every roll
| Piece | Wall | Across | Up the wall | Cut | Roll · position |
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Rolls
| Roll | Drops | Used | Tail |
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Drops are placed longest first into the first roll with room. Select a drop to read where on the wall it sits and where on the roll it is cut.
Why three bolts, not two
Take the example wall, 12 feet wide and 8 feet high, and an American bolt of 20.5 inches by 33 feet with a 21-inch straight-match repeat. Twelve feet is 144 inches, and 144 divided by 20.5 is 7.02, so the wall takes eight drops, the last one an inch wide. Each drop must be 96 inches plus 4 inches of trim, 100 inches, cut to whole repeats: five repeats are 105 inches. A 33-foot bolt is 396 inches and yields three such drops with 81 inches left; the fourth drop opens a second bolt, the seventh a third. Three bolts, 8 drops, 70 feet of cuts, 40 inches lost to the repeat and 32 to trim.
The area method takes 96 square feet, adds 10 percent and divides by the 56.4 square feet on the bolt: 1.87, rounded to two. Two bolts hold six drops; the wall needs eight. The estimator that told a shopper two rolls was wrong by a third, and the shopper finds out when the last two drops are missing.
What a door does, drop by drop
Switch on the first opening: a 41-inch door, 80 inches high, starting 20.5 inches from the left. It spans the second and third drops completely, so those two become 16-inch pieces above the door, each cut to one repeat of 21 inches. The order falls to two bolts, because 105 + 105 + 105 + 21 + 21 fits in one bolt with 39 inches to spare. Move the door to start at 10 inches and it straddles a seam on both sides: no drop clears it, nothing is shortened, and three bolts stand. Subtracting the door’s area, as most estimators do, cannot tell those two cases apart.
A room against a manufacturer’s chart
Room mode papers four walls of 12, 10, 12 and 10 feet at 8 feet: 28 drops, and at three per bolt, ten bolts. York Wallcoverings publishes a chart for its 56-square-foot bolt that gives six bolts for a 10-by-12 room with an 8-foot ceiling, and it notes that larger repeats need more. The gap is the repeat and the trim: with a random match and no trim allowance each bolt yields four drops of 96 inches and the same room takes seven bolts. Enter the label values and the plan says which of those rooms is yours.
Roll formats publishers state
| Publisher | Format stated |
|---|---|
| York Wallcoverings | 1 bolt = 56 ft², 20.5 in × 33 ft; 1 bolt covers about 6 ft of wall up to 9-ft ceilings; deduct 1 bolt for every 4 ordinary doors or windows — bolts by room size, 8-ft / 9-ft ceiling: 8×10 → 5 / 6; 10×10 → 6 / 6; 10×12 → 6 / 7; 10×14 → 7 / 7; 12×12 → 7 / 7 (chart continues); PDF 'how-much-wallpaper.pdf' linked |
| Wallpaper Direct (US page) | 'Estimates are based on a standard roll size of 52 cm × 10 m' |
| Painted Paper | rolls 24 in W × 13 ft L or 24 in W × 27 ft L; 8.5 × 10 in sample; 24 × 36 in preview panel; product repeats seen: 24 in (Odette Arboretum, Luca Bloom) and 48 in ('this pattern needs at least 2 rolls'); on-page estimator with roll size choice and height limit 31 ft 2 in |
| Phillip Jeffries | sold by the linear yard; roll widths 36, 45 and 54 in selectable; results rounded up to the next whole yard; 10 % more recommended |
| Schumacher | Deux Par Deux Ground 5000640: roll width 36 in, 4 yards per roll, coverage 36 sq ft, random match, order minimum 144 in × 36 in (one roll); item 5000670: 36 in, 4.5 yards, 40.5 sq ft; no calculator published |
The first result for this query tells American shoppers that its estimate is based on a 52-centimetre by 10-metre roll. The bolt on an American shelf is 20.5 inches by 33 feet, and a boutique roll can be 24 inches by 13 feet. Enter the one on your label; the calculator assumes none.
Schumacher publishes no calculator, only roll records: the Deux Par Deux Ground read for this page is 36 inches wide, 4 yards a roll, 36 square feet, random match, with an order minimum of one roll of 144 by 36 inches; a sister item runs 4.5 yards and 40.5 square feet. On the example wall a 36-inch roll takes exactly four drops. With a 4-inch trim each drop is 100 inches, so a 144-inch roll yields one drop and 44 inches over, and the 162-inch roll one drop and 62 over: four rolls either way. Divide 96 square feet by 36 and the answer is 2.67, three rolls, one short of what the wall cuts.
What the other estimators multiply
Of the tools executed for this page, Thibaut returned four rolls for the example wall with the repeat and two without, from width times height and a rounded height; Omni rounds the wall height up to whole repeats and divides area by roll area; Wallpaper Direct adds a fixed 10 percent and, in two attempts, ignored the repeat that was entered. Romo alone offers a straight, half-drop or random choice. None places a drop on a roll or a door on a wall. The source register keeps the executed inputs and outputs.
Half-drop and multiple-drop matches, and what each costs per drop, are worked through on the pattern repeat page; wide trade goods sold by the linear yard have their own yardage planner; the Painted Paper planner fixes the roll at 24 inches by 13 or 27 feet with that vendor’s prices; the York bolt planner re-cuts that maker’s room chart in drops. All four use this page’s drop engine.
Questions before the first drop
How does this calculator count rolls?
It lays the drops first. Each wall gets as many drops as its width divided by the roll width, rounded up. Each drop is cut to the wall height plus a trim allowance, rounded up to whole repeats. The cut lengths are then placed on rolls, longest first, and the number of rolls that had to be opened is the answer.
How do I measure a wall for wallpaper?
Width along the baseboard, height from baseboard to ceiling line at the tallest point, and for each door or window its width, height, distance from the left edge and sill height. The position matters here: an opening only saves paper on the drops it spans completely.
How do I account for a pattern repeat?
Enter the vertical repeat from the label and the match type. With a straight match every drop is cut to whole repeats; with a half-drop match alternate drops carry an extra half repeat before rounding; a random match needs no rounding. The example wall shows the three totals side by side.
Is there a version with repeat only?
The repeat lives in this calculator; the companion page on pattern repeat goes deeper into straight, half-drop and multiple-drop matches and what each does to the cut length. Both use the same drop engine, so a plan started here can be checked there with the same numbers.
Can it do a single feature wall?
Single wall is the default mode: one width, one height, up to two openings. The example is a 12-by-8-foot wall on a 20.5-inch bolt with a 21-inch repeat: eight drops, three bolts. Switch to room mode for four walls sharing the same rolls.
How much wallpaper does a 12-by-12 room need?
Four walls of 12 feet at 8 feet need 32 drops on a 20.5-inch bolt. With a 21-inch repeat and a 4-inch trim each drop is cut to 105 inches and a 33-foot bolt yields three, so eleven bolts. With a random match and no trim a bolt yields four drops and eight bolts suffice. The chart on a manufacturer’s site gives seven for that room, which is the area method.
Why does the square-foot method give fewer rolls?
Because a roll is a length of strips, not a sheet of area. A 56-square-foot bolt cannot cover 56 square feet of wall when each drop wastes the rounding to the repeat and the trim, and when the last drop of a bolt is too short to use. The ledger prints both numbers so the gap is visible.
Can I enter fractional inches?
Yes. Every length field accepts feet and inches with fractions, such as 8 ft 6 1/2 in or 20 1/2 in, and the plan reports cut lengths in feet and inches. Whole-inch entry is a limitation of the retailer tools audited, not of measuring tape.
Does a square wall change anything?
Only the drop count. A 96-by-96-inch wall takes five drops on a 20.5-inch roll, with the last one 14 inches wide. The cut length per drop is the same as any wall of that height, so rolls follow from the number of drops and the repeat.
What makes a wallpaper calculator good?
It should show the drops, not just a total: how many, how long each is cut, which roll supplies it, and what is left on that roll. It should let you place a door rather than subtract its area, and it should let you enter the roll you are actually buying instead of a default format.
Is this wallpaper calculator free?
Yes. The drop plan, roll sheet, comparison table and CSV are available without an account or email. The preloaded bolt, repeat and trim are example values; the roll formats table lists what several publishers state so you can enter the one on your label.
Is there an app or a saved plan?
The calculator runs in the browser and stores nothing on a server. Print the plan, download the CSV of pieces and rolls, or export the wall drawing as SVG before leaving. It re-computes on every keystroke, so re-entering the label values at the store takes a minute.
What the drop plan does not decide
- Rectangular walls only; no sloped ceilings, stairwells, chimney breasts or borders. Up to two positioned openings.
- Half-drop is modeled as half a repeat added to alternate drops before rounding; multiple-drop and offset matches are entered as their effective repeat.
- Drops are placed on rolls longest first; a hanger may cut in a different order, and short pieces may come from tails the model does not reuse across walls.
- Trim allowance is one value per drop. Ceiling-line and baseboard cuts on an out-of-level room may need more.
- No prices, adhesive, primer or booking times. Roll formats in the table are quoted from their publishers, not verified against a delivered roll.