Room & Wallpaper Details

Room Length (ft)

Room Width (ft)

Wall Height (ft)

Number of Doors

Number of Windows

Roll Width (in)

Roll Length (ft)

Pattern Repeat (in)

Rolls Needed

Net wall area

Coverage per roll

Always buy from the same batch. Consider buying 1 extra roll for pattern matching and future repairs.

How to Use

1
Enter the room length, width, and wall height in feet
2
Enter the number of doors and windows to subtract their area
3
Check your wallpaper packaging for the roll width (usually 20.5 in) and roll length (usually 33 ft for a US single roll)
4
If your wallpaper has a repeating pattern, select the closest repeat size to account for matching waste

Formula

Net Wall Area = 2 × (Length + Width) × Height − Openings

Rolls = ⌈(Net Area × Pattern Factor) ÷ Roll Coverage⌉

Roll coverage is calculated as roll width (in ft) × roll length (ft). The pattern factor adjusts for the extra height lost aligning each strip's repeat: (wall height + repeat) ÷ wall height.

Examples

Bedroom: 12 × 10 ft, 8 ft walls, 1 door, 1 window, no pattern

Perimeter 44 × 8 = 352 − 36 = 316 sq ft net. Roll coverage = (20.5/12) × 33 = 56.4 sq ft. 316 ÷ 56.4 = 5.6

Result: 6 rolls

Living room: 16 × 13 ft, 9 ft walls, 2 doors, 3 windows, 12 in pattern repeat

Perimeter 58 × 9 = 522 − 87 = 435 sq ft net. Pattern factor = (9 + 1) / 9 = 1.11. 435 × 1.11 ÷ 56.4 = 8.56

Result: 9 rolls

FAQ

A US single roll is the standard unit (about 56 sq ft). Wallpaper is often sold in double rolls (two single rolls on one spool) but priced per single roll. This calculator uses single-roll coverage. Check your packaging carefully.

Most wallpaper projects cover only the walls. If you plan to wallpaper the ceiling too, calculate it separately by entering the ceiling dimensions as a separate room with a height of 0 (or use a fixed roll count based on area).

Look for a symbol on the packaging: a straight arrow with a number (e.g., ↕ 12 in) means a straight match; an offset arrow (e.g., ↕↕ 12 in) means a drop match. Measure between identical points on the printed pattern to confirm.

Pro Tip

Always buy at least one extra roll from the same batch (same lot number). If you need to patch a damaged section later, matching the exact pattern and dye lot after the product is discontinued can be nearly impossible.