What is the difference between a single roll and a double roll?

Wallpaper Calculator

Determine how many rolls of wallpaper you need based on room dimensions, pattern repeat, and openings.

Room Dimensions

Length (ft)

Width (ft)

Height (ft)

Roll & Pattern Details

Roll Width (in)

Roll Length (ft)

Repeat (in)

Doors to Subtract

Windows to Subtract

Wallpaper Results

SPEC_VERIFIED

Double Rolls Needed

10rolls

Detailed Material Breakdown

Net Wall Area: 397 sq ft
Total Wall Area (gross): 442 sq ft
Deductions (doors & windows): 45 sq ft

Calculation Formula & Assumptions

Calculates wallpaper rolls needed based on room perimeter, wall height, vertical pattern repeat, and opening deductions.

Rolls Needed = ⌈Total Wall Strips ÷ Usable Strips Per Roll⌉

Step-by-step breakdown:

Compute room perimeter = 2 × (Length + Width)
Compute total wall area = Perimeter × Wall Height
Subtract doors and windows to get net wall area
Calculate usable strips per roll based on wall height plus pattern repeat allowance
Divide total required strips by usable strips per roll and round up to whole rolls.

Note: Double rolls (bolts) typically cover 56 to 60 sq ft of flat wall space, yielding about 48 to 50 sq ft of usable pattern coverage.

Worked Calculation Example

Dining Room Accent Wall (12 ft wide × 9 ft high)

Papering a dining room wall with a patterned wallpaper with a 18" repeat.

Wall Dimensions:12 ft wide × 9 ft high (108 sq ft)

Roll Size:20.5 inches wide × 33 feet long (56.3 sq ft)

Pattern Repeat:18 inches (1.5 ft)

Calculation Steps:

Strips needed = (12 ft × 12 in/ft) ÷ 20.5 in = 7.02 => 8 strips
Cut length per strip = 9 ft ceiling + 1.5 ft repeat + 0.33 ft trim = 10.83 ft
Strips per 33-foot roll = 33 ÷ 10.83 = 3.04 => 3 usable strips per roll
Rolls needed = 8 strips ÷ 3 strips/roll = 2.67 => 3 double rolls

Order 3 double rolls of wallpaper.

How to Use This Calculator

Enter room length, width, and ceiling height.
Enter roll dimensions (standard US double roll is 20.5" wide × 33' long).
Enter vertical pattern repeat (0 for solids/textures; 12" to 24" for repeating motifs).
Input count and dimensions of doors and windows to deduct.

Common Estimation Mistakes to Avoid

Neglecting pattern repeat: a 24-inch pattern repeat can discard up to 25% of the roll length in matching scrap.
Purchasing single rolls when wallpaper is packaged in double-roll bolts.

Frequently Asked Questions

A single roll is an industry unit of measurement (~28 sq ft), but wallpaper is almost universally packaged as continuous double rolls (~56 sq ft) to reduce cutting scrap.