This calculator is one piece of the SiteScope takeoff engine. See roll counts for the whole room from a 3D scan.

Free Tool

Wallpaper Calculator: How Many Rolls Do You Need?

Rolls = strips needed / strips per roll, rounded up. Enter the room, roll size, and pattern repeat to get strip count and rolls, with seam overlap and pattern waste applied. Same math as the SiteScope app.

1 Room Dimensions

Length (ft)

Width (ft)

Height (ft)

Baseboard height (in)

Strips end above baseboard

Crown molding height (in)

Strips end below crown

Note on openings: Strips hang continuously over doors and windows and are trimmed after hanging. This calculator uses the conservative approach: door and window widths are not deducted from your strip count.

2 Roll Size

Roll Width (inches)

American standard: 27 in

Roll Length (feet)

American standard: 27 ft

Presets:

Seam Overlap (inches)

0" for butt seam (standard). Overlap used for commercial vinyls. Difference.

Installer Buffer (%)

Added on top of pattern math. Covers cut errors, damaged strips, and dye-lot reserve. Pros use 10 to 15 percent.

3 Pattern & Match Type

Match Type

Pattern Repeat Length (inches)

Each strip must start at the same point in the pattern cycle, so strips are cut longer than the wall height to align seams. Common repeats: 18", 24", 27". Set to 0 for no repeat.

Results

Room perimeter

Strip height

Cut per strip

Strips needed

Strips per roll

Material (linear yd)

Rolls to order

rolls

Paper purchased

Order all rolls from the same dye lot. The installer buffer above already accounts for cut errors and dye-lot reserve.

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Also need paint?

Use the Paint Calculator to get gallons per coat, surface-type adjustments, primer, and 5-gal pail breakdown.

These estimates use the same formulas as the SiteScope app. Actual quantities depend on wall conditions, installer technique, and product specifications. Always verify with your supplier before ordering.

How to Calculate Wallpaper Rolls

Wallpaper is bought by the roll but hung by the strip. Work out how many strips go around the room, how many full strips one roll yields once the pattern repeat is added, and divide. Then add a buffer.

Worked example: 12 x 14 ft room, 9 ft walls, 27 in x 27 ft rolls

Perimeter: 2 x (12 + 14) = 52 ft = 624 in
Strips: 624 / 27 = 23.1, round up to 24 strips
Cut length with a 21 in straight repeat: 108 in wall rounds up to 6 repeats = 126 in
Strips per roll: 324 in roll / 126 in = 2.57, so 2 full strips
Rolls: 24 / 2 = 12, plus a 10% buffer = 13.2, round up to 14 rolls

The same room with no repeat yields 3 strips per roll: 8 rolls, or 9 with the buffer. The repeat alone costs 5 rolls.

More detail in how many rolls of wallpaper you need and per-roll vs per-square-foot pricing.

Frequently Asked Questions

How many rolls of wallpaper do I need for a 12x14 room?

With 9 ft walls and 27 in x 27 ft rolls, the 52 ft perimeter needs 24 strips. With no pattern repeat, each roll yields 3 full-height strips, so 8 rolls, or 9 with a 10% buffer. With a 21 in straight repeat, each strip is cut to 126 in, so only 2 fit per roll: 12 rolls, or 14 with the buffer.

Why do I need more rolls when the pattern has a repeat?

Every strip has to start at the same point in the pattern so the seams match. That means each cut is rounded up to a whole number of repeats, and the extra is waste. Bigger repeats and taller walls waste more.

How does half-drop or quarter-drop match change the count?

Drop matches shift the pattern from strip to strip. This calculator, like the SiteScope app, plans half-drop on a two-strip cycle (2x the repeat) and quarter-drop on a four-strip cycle (4x the repeat). That is conservative on purpose, so you are not short on install day.

Does the calculator subtract doors and windows?

No. It figures strips around the full perimeter, which is the conservative installer rule because strips above and below openings still use roll length. In SiteScope, openings are mapped to their positions on each wall, and the continuous elevation can show where a full repeat falls behind an opening.

What is a seam overlap and when do I use it?

Most residential papers are hung with a butt seam (0 in overlap). Some commercial vinyls are overlapped and double-cut, so each strip advances less than its full width and you need more strips.

How much extra wallpaper should I order?

Many installers add 10 to 15 percent for cutting errors, damage, and future repairs, and order every roll from the same dye lot. The buffer field applies that on top of the pattern math.

See it in the app

Add cutouts, doors, and windows. See exactly where every strip lands.

In SiteScope, add wallpaper to a room from a 3D floor plan. Strips are cut to the tallest wall and rolls are counted for the room. The continuous elevation shows every seam, roll boundary, and pattern repeat. Openings are mapped to exact positions so you know which repeats fall behind doors and windows before you order.

Continuous wall elevation showing strip layout, roll count, and pattern saves

Continuous elevation: strip seams (S1–S30), roll boundaries (R1–R10), and pattern saves highlighted in green where repeats fall behind openings

Wallpaper assignment card showing perimeter, strips, repeats, pattern saves, cost and margin

Custom openings per wall

Add exact door and window positions. Cutout regions excluded from strip placement, not just averaged out.

Pattern save detection

Identifies pattern repeats that fall entirely behind openings, shown in green, counted as potential savings in the assignment card.

Kill point planning

Set the start position and papering direction, then see the seam layout across all walls before hanging a single strip.

Cost, charge, and margin per roll

Enter your cost and charge per roll. SiteScope applies them and totals them on the Estimate page. Free includes estimating with up to 10 materials. Unlimited materials and quote PDFs are on Pro.

Try SiteScope Free

Estimating this for clients? See SiteScope for wallpaper contractors.