Wallpaper Amount Calculator
Calculate how many rolls of wallpaper you need for any room.
Accounts for doors, windows, and pattern repeat.
Wallpaper Needed
Wallpaper calculations require knowing your wall area, the roll dimensions, and the pattern repeat distance. Getting this wrong means either running short mid-project or buying too many expensive rolls.
Standard roll sizes:
- US standard single roll: 27 inches wide × 13.5 feet long = 30.4 sq ft (usable: ~25 sq ft after trimming)
- US double roll: 27 inches wide × 27 feet long = 60.75 sq ft (usable: ~50 sq ft)
- European standard: 20.5 inches wide × 33 feet long = 56.4 sq ft (usable: ~46 sq ft)
Pattern repeat types:
- Random/no match — No pattern alignment needed. Least waste (5–10%).
- Straight match — Pattern aligns at the same height on each strip. Moderate waste (10–15%).
- Drop match — Pattern aligns at half the repeat distance. Most waste (15–25%).
The formula:
- Calculate total wall area: Perimeter × Height
- Subtract openings: Doors (21 sq ft each) + Windows (15 sq ft each)
- Divide net area by usable coverage per roll
- Add waste factor for pattern matching
- Round up to next whole roll
Pattern repeat impact: A 24-inch (61 cm) pattern repeat on an 8-foot wall means you lose up to 24 inches per strip in alignment waste. Smaller repeats (under 12 inches) waste less.
Buying tips:
- Always buy from the same dye lot (batch number) to ensure consistent color
- Buy 1–2 extra rolls beyond the calculation for mistakes, repairs, and future patches
- Most stores allow returns of unopened rolls within 30–60 days
- Measure twice, order once — running short mid-project means waiting for new stock
Tip: Wallpaper is sold as single rolls but usually packaged as double rolls. Always confirm with your retailer whether the roll length listed is single or double before calculating.