How to Use This Calculator
- Enter your room length, width, and ceiling height.
- Set the number of doors and windows — the calculator subtracts their area automatically.
- Choose your roll size (US or Euro standard) and waste factor based on pattern complexity.
- Read your result — number of rolls, net wall area, and total coverage needed with waste.
Wallpaper Roll Sizes
| Roll Type | Width | Length | Coverage |
|---|---|---|---|
| US Standard Single | 20.5 inches | 33 feet | 56.4 sq ft |
| Euro Standard | 21 inches | 33 feet | 57.75 sq ft |
| US Double | 20.5 inches | 56 feet | 95.7 sq ft |
| Euro Double | 21 inches | 56 feet | 98 sq ft |
How Much Waste Should I Plan For?
Waste depends on the wallpaper pattern. Solid colors or textures without a repeat need only 5% extra. Small pattern repeats (under 6 inches) need 10%. Large-scale patterns with 12+ inch repeats can waste 15-20% because you have to align each strip.
If this is your first wallpaper project, add 15-20% for learning mistakes. Even experienced hangers keep one extra roll on hand.
Wallpaper Rolls by Room Size
| Room Size | Wall Area | Standard Rolls | Double Rolls |
|---|---|---|---|
| 10 x 10 ft (8 ft ceiling) | ~280 sq ft | 6 rolls | 3 rolls |
| 12 x 12 ft | ~336 sq ft | 7 rolls | 4 rolls |
| 14 x 16 ft | ~420 sq ft | 9 rolls | 5 rolls |
| 16 x 20 ft | ~504 sq ft | 10 rolls | 6 rolls |
Tips for Hanging Wallpaper
- Start at the most visible wall — so pattern mismatches end up in an inconspicuous corner.
- Use a plumb line — walls are rarely perfectly straight. A plumb line on each new wall keeps strips vertical.
- Book the paste — fold pasted strips back on themselves for 3-5 minutes before hanging. This lets the paper expand evenly.
- Smooth from the center outward — use a smoothing brush or plastic smoother to push out air bubbles.
FAQ
Should I buy single or double rolls?
Most wallpaper is sold in double rolls, even if priced per single roll. Double rolls reduce waste because you get longer strips with fewer seams. Always check what the manufacturer ships.
How do I wallpaper around corners?
Never wrap a full strip around an inside corner — the paper will wrinkle. Instead, cut the strip to wrap 1/2 inch around the corner, then start a new plumb strip on the next wall overlapping by 1/4 inch.
Can I wallpaper over existing wallpaper?
It is possible with vinyl-over-vinyl adhesive, but not recommended. The old paper can bubble or peel, ruining the new layer. Strip the old wallpaper first for the best results.