How to Calculate How Much Wallpaper You Need

How to Calculate How Much Wallpaper You Need

Wallpaper is sold in single or double rolls, and calculating the right amount requires accounting for room dimensions, pattern repeats, and cuts around doors and windows.

Step 1: Measure Total Wall Area

Measure the perimeter (total linear footage) of the walls × ceiling height.

Example: Room perimeter = 52 linear feet (sum of all wall widths), ceiling height = 9 ft. Total wall area = 52 × 9 = 468 sq ft

Step 2: Subtract Openings

• Average door: 21 sq ft
• Average window: 15 sq ft

468 − 21 − 15 = 432 sq ft

Step 3: Account for Coverage Per Roll

A standard US single roll covers approximately 25–30 sq ft usable (the roll is sold as more, but you lose material to trimming).

432 / 28 = 15.4 → 16 single rolls (or 8 double rolls)

Step 4: Add for Pattern Repeat

Pattern repeat means you must align the pattern at each seam, wasting material.

For a 12-inch repeat: 16 rolls × 1.15 = 18.4 → order 19 single rolls

Practical Tips

• Always round up—dye lots vary between manufacturing runs
• Save leftover rolls for future repairs
• Use a wallpaper calculator for irregular rooms with many openings

Use our wallpaper calculator for any room dimensions.