Utility
Wallpaper Calculator
Calculate how many rolls of wallpaper you need, accounting for doors, windows, and pattern repeat waste.
Enter room dimensions and click Calculate
How is this calculated?
Perimeter = 2 × (Length + Width)
Total Wall Area = Perimeter × Height
Door deduction = Doors × 21 sq ft (3×7 ft standard)
Window deduction = Windows × 15 sq ft (3×5 ft standard)
Usable Wall Area = Total Wall Area - Doors - Windows
Roll coverage = Roll Width (ft) × Roll Length (ft)
Standard: (20.5/12) × 33 = 56.4 sq ft/roll
Pattern waste factor:
No repeat: 10% waste
Small (≤12"): 15% waste
Large (>12"): 20-25% waste
Rolls needed = Usable Area ÷ (Roll coverage × (1 - waste%))FAQ
Frequently asked questions about wallpaper
How many rolls of wallpaper do I need?
Measure total wall area (perimeter × height), subtract doors and windows, then divide by the usable area per roll. A standard US roll covers about 28 sq ft usable after waste. Add 10-15% for pattern matching and mistakes.
What is a pattern repeat and why does it matter?
Pattern repeat is the distance before the design repeats vertically. Larger repeats (12-24 inches) create more waste because you need to align patterns between strips. A 24-inch repeat can waste 20-30% more paper versus a plain/random match.
What size is a standard wallpaper roll?
US standard rolls are 20.5 inches wide × 33 feet long (about 56 sq ft total). European rolls are typically 21 inches × 33 feet. Some brands sell double rolls (56 sq ft usable). Always check your specific product dimensions.
Should I order extra wallpaper?
Yes, always order 10-15% extra. You need extra for: pattern matching waste, cutting around outlets/corners, potential mistakes during hanging, and having spare for future repairs. Dye lots can vary between batches.
How do I measure a room for wallpaper?
Measure each wall's width and the room's height (floor to ceiling or to where you want the paper to stop). Multiply perimeter by height for total area. Subtract standard door (21 sq ft) and window (15 sq ft) openings.
Can I wallpaper over existing wallpaper?
It's not recommended. Old wallpaper may bubble, peel, or show through. For best results, remove old paper, repair the wall surface, apply primer/sizing, then hang new paper. Exception: vinyl-over-vinyl removal can damage drywall, so sometimes a liner paper is used.