How many rolls of wallpaper do you need?
Rollsy is a free wallpaper roll calculator for DIY homeowners and first-time buyers. Measure wall by wall, subtract doors and windows, handle half-drop repeats, and walk out with a shopping list the cashier can actually read.
10%extra for trim & match
Wallpaper reference: roll dimensions, drop tables, pattern symbols, opening deductions
The calculator above estimates how many rolls a room needs given wall geometry, opening cutouts, pattern repeat, match type, and a waste buffer. The reference below covers the lookup material behind the calculation: roll dimensions in US and European markets, the international pattern-symbol legend printed on every bolt, drops-per-roll tables, deduction values for standard openings, and imperial-metric conversions.
Standard roll dimensions by region and bolt type
Wallpaper ships in different physical formats depending on the manufacturer and market. The number on the label is what the calculator needs.
| Bolt type | Width | Length | Coverage (flat) | Notes |
|---|---|---|---|---|
| US single roll | 20.5 in | 16.5 ft | 28.2 sq ft | Rare on shelves; most US bolts ship as doubles |
| US double roll | 20.5 in | 33 ft | 56.4 sq ft | Standard US format; two singles joined on one bolt |
| European standard | 53 cm (20.87 in) | 10.05 m (33 ft) | ~56.7 sq ft | Equivalent to a US double; the global default |
| Euro narrow roll | 50 cm (19.69 in) | 10 m (32.8 ft) | ~53.8 sq ft | Heritage and reproduction lines |
| Wide commercial vinyl | 54 in | 30 yd | 405 sq ft | Hospitality and contract wallcovering |
| Grasscloth and natural fiber | 36 in | 24 ft | 72 sq ft | Often ships untrimmed; lose ~1 in per edge |
| Peel-and-stick (typical) | 24 in | 12–16 ft | 24–32 sq ft | Varies by brand; check SKU spec sheet |
European bolts dominate global supply: a UK or German import labeled “10 m roll” is sized like a US double regardless of how the retailer shelves it.
Pattern repeat ranges by design family
Field-observed repeat ranges for the design categories that account for the majority of residential SKUs.
| Design family | Typical repeat range | Match type | Why |
|---|---|---|---|
| Solids and grass cloths | 0 in | No match | No motif to align |
| Linen and woven textures | 0–2 in | No match or random | Subtle texture; strict alignment not required |
| Small geometrics (dots, micro-grid) | 1–4 in | Straight | Short cycle, easy alignment |
| Vertical stripes | 1–6 in horizontal pitch | Straight | Vertical lines need horizontal step |
| Trellis and lattice | 6–12 in | Straight or half-drop | Mid-cycle; half-drop common in classic patterns |
| Florals, damasks, toile | 18–27 in | Half-drop | Large motifs; half-drop softens the visual grid |
| Murals and panoramics | Sold by panel set | Numbered panels | Order by mural diagram, not repeat |
| Modern oversized prints | 24–36 in | Straight | Designer studios push repeat for visual scale |
If the bolt label is missing the repeat value, measure it directly: pick a feature in the design, walk the bolt down until that feature appears again, and measure the vertical distance.
Pattern symbols on bolt labels
International wallcovering symbols from CEN EN 233 and the parallel Wallcoverings Association standards. These pictograms appear on every European bolt and most US imports.
| Symbol | Name | Meaning |
|---|---|---|
| Single arrow up | Straight match | Pattern aligns directly across drops; no offset |
| Half-arrow / offset arrow | Offset match (half-drop) | Adjacent drops shifted by half a repeat |
| Crossed arrows | Free match | No alignment required; hang any direction |
| Brush and roller | Paste-the-wall | Apply paste to the drywall, hang dry paper |
| Roller alone | Paste the paper | Apply paste to the back of the paper |
| Bucket / submerged paper | Pre-pasted | Wet the paper in a water tray to activate paste |
| Scissors with dashed line | Pre-trimmed | Edges factory-cut; butt seams directly |
| Scissors with solid stripe | Untrimmed | White selvage; trim 1 in per side before hanging |
| Single / double / triple wave | Spongeable / washable / scrubbable | Cleaning durability tier |
| Sun | Lightfast | Resistant to fading from sunlight |
| Flame with shield | Class A fire rating | Commercial use; ASTM E84 < 25 |
| Two arrows opposite | Reverse-hang | Flip every other drop 180° to hide shading |
The reverse-hang symbol matters most for solids and grass cloths: a slight color shift along one edge of the bolt becomes visible at every seam unless alternate drops are flipped during install.
Drops per roll quick lookup
For a US double roll (33 ft, 396 in). Read across: find the adjusted drop height after pattern-repeat rounding, then count drops you can cut from one bolt.
| Wall height | Pattern repeat | Match type | Adjusted drop | Drops per double roll |
|---|---|---|---|---|
| 8 ft (96 in) | 0 in | No match | 96 in | 4 |
| 8 ft (96 in) | 18 in | Straight | 108 in | 3 |
| 8 ft (96 in) | 21 in | Straight | 105 in | 3 |
| 8 ft (96 in) | 27 in | Half-drop | 108 in plus alt offset | 3 |
| 9 ft (108 in) | 0 in | No match | 108 in | 3 |
| 9 ft (108 in) | 18 in | Straight | 108 in | 3 |
| 9 ft (108 in) | 21 in | Half-drop | 126 in | 3 |
| 10 ft (120 in) | 0 in | No match | 120 in | 3 |
| 10 ft (120 in) | 21 in | Half-drop | 126 in | 3 |
| 12 ft (144 in) | 0 in | No match | 144 in | 2 |
| 12 ft (144 in) | 21 in | Half-drop | 168 in | 2 |
The cliff at 12-ft ceilings is the most common over-order trap: any wallpaper with a repeat above ~15 in drops a bolt from 3 drops per roll to 2, raising the roll count by 50%.
Standard opening dimensions for deductions
Used for cutout subtraction in roll-count math. Rough opening dimensions, not finished trim sizes.
| Opening | Width | Height | Area (sq ft) |
|---|---|---|---|
| Standard interior door | 32 in | 80 in | 17.8 |
| Wide interior door (closet) | 36 in | 80 in | 20.0 |
| Pocket door | 32 in | 84 in | 18.7 |
| Bifold closet door | 60 in | 80 in | 33.3 |
| French door pair | 60 in | 80 in | 33.3 |
| Standard single window | 36 in | 48 in | 12.0 |
| Casement window | 30 in | 48 in | 10.0 |
| Picture window | 60 in | 48 in | 20.0 |
| Bay window opening | 96 in | 48 in | 32.0 |
| Pass-through / cased opening | 60 in | 84 in | 35.0 |
| Built-in shelving recess | 36 in | 96 in | 24.0 |
| Fireplace opening (firebox plus mantel) | 60 in | 60 in | 25.0 |
Openings smaller than about 2 square feet (transoms, small vents, electrical boxes) can usually be ignored in roll math because rounding absorbs them.
Coverage shortcuts
For back-of-envelope estimates or sanity-checking the calculator’s output.
| Configuration | Usable coverage per US double roll |
|---|---|
| No-match, 8 ft walls | ~54 sq ft |
| No-match, 9 ft walls | ~46 sq ft |
| No-match, 10 ft walls | ~38 sq ft |
| 21-in straight match, 8 ft walls | ~45 sq ft |
| 27-in half-drop, 9 ft walls | ~31 sq ft |
The “56 sq ft per roll” number printed on US double-roll labels assumes zero pattern repeat and zero trim waste. Real usable coverage is always less.
Imperial / metric conversions
Wallpaper specs cross unit systems often. European bolts ship in centimeters and meters; US calculators expect inches and feet.
| Measurement | Imperial | Metric |
|---|---|---|
| Standard US bolt width | 20.5 in | 52.07 cm |
| European bolt width | 20.87 in | 53 cm |
| US double-roll length | 33 ft | 10.06 m |
| European bolt length | 32.97 ft | 10.05 m |
| 8 ft wall | 8 ft | 2.44 m |
| 9 ft wall | 9 ft | 2.74 m |
| 10 ft wall | 10 ft | 3.05 m |
| 18 in pattern repeat | 18 in | 45.72 cm |
| 21 in pattern repeat | 21 in | 53.34 cm |
| Untrimmed selvage margin | 1 in per side | 2.54 cm per side |
| 1 sq ft | 1 sq ft | 0.0929 sq m |
| 1 sq m | 10.76 sq ft | 1 sq m |
When a spec sheet mixes units (a US import with metric bolt dimensions), convert everything to one system before entering values in the calculator.
Calculation reference
The formulas the calculator runs, written out for hand-checking.
adjusted_drop_no_match = wall_height adjusted_drop_straight = ceil(wall_height / repeat) * repeat adjusted_drop_half_drop = adjusted_drop_straight + (repeat / 2) on alternating drops usable_wall_area = sum_walls (width * height) - sum_openings (width * height) drops_per_roll = floor(roll_length / adjusted_drop_height) drops_needed = sum_walls ceil(wall_width / roll_width) raw_rolls = drops_needed / drops_per_roll rolls_to_buy = ceil(raw_rolls * (1 + waste / 100))
All lengths in consistent units (in or cm). repeat is 0 for no-match patterns. waste is a percent (10 means 10%). roll_width is the trimmed width if the bolt ships untrimmed.
Worked example: accent wall, 21-in straight match
Feature wall 14 ft wide × 9 ft tall (168 × 108 in), papered in a 21-in straight-match floral. US double-roll bolt, 20.5 in × 33 ft. Buffer 10%.
adjusted_drop = ceil(108 / 21) * 21
= ceil(5.14) * 21
= 6 * 21
= 126 in
drops_per_roll = floor(396 / 126)
= floor(3.14)
= 3
drops_needed = ceil(168 / 20.5)
= ceil(8.20)
= 9 drops
raw_rolls = 9 / 3 = 3 rolls
rolls_to_buy = ceil(3 * 1.10) = ceil(3.3) = 4 double rollsFor a full four-wall room, repeat the drops_needed calculation per wall, sum across walls, divide by drops_per_roll once at the end, then round up.
Related concepts
- Batch / dye lot
- a code printed on every wallpaper bolt identifying the production run. Two bolts with different batch codes can show visible color differences even at the same SKU. Always order from a single batch; the print shopping list reserves a write-in field for the batch code.
- Repeat vs match type
- repeat is the vertical cycle in inches; match type is how adjacent drops align. A pattern can have any repeat with any match type; the two are independent.
- Drop
- a single vertical strip of wallpaper cut to wall height (or the adjusted drop height when there is a repeat). Bolts are divided into drops; rolls are bought in whole units.
- Selvage
- the white margin on either side of untrimmed wallpaper, sliced off with a straightedge before hanging. Modern paper ships pre-trimmed; selvage trimming is a heritage-product workflow.
- Wallpaper symmetry groups
- in crystallography, the 17 wallpaper groups describe every possible repeating 2D pattern. Commercial wallpaper uses a small subset (p1 for free-match, p2 for half-drop, pm and pg for straight-match designs).