Wallpaper Calculator
A 12×14 ft room with 9 ft ceilings needs 8-10 single rolls of standard US wallpaper (with pattern repeat). Budget $160-800 depending on paper quality.
Wallpaper Calculator
Enter your project dimensions for instant results.
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How to Calculate Wallpaper
The formula accounts for pattern repeat waste:
usable_strip_length = ceiling_height + pattern_repeat - (ceiling_height % pattern_repeat)
strips_per_roll = Math.floor(roll_length / usable_strip_length)
total_strips = Math.ceil(room_perimeter / roll_width) - door_windows_strips
rolls_needed = Math.ceil(total_strips / strips_per_roll)
| Type | Width | Length | Coverage (no waste) |
|---|---|---|---|
| US single roll | 20.5″ | 16.5 ft (5m) | 28 sq ft |
| US double roll (bolt) | 20.5″ | 33 ft (10m) | 56 sq ft |
| Euro standard | 20.5″ | 33 ft (10m) | 56 sq ft |
| Wide Euro | 27″ | 33 ft (10m) | 74 sq ft |
| Commercial (54″) | 54″ | 30 yd (90 ft) | 405 sq ft |
| Pattern Repeat | Waste per Strip (9 ft ceiling) | Effective Coverage |
|---|---|---|
| 0″ (no repeat / texture) | 0% | Full roll yield |
| 6″ | 5-8% | 26 sq ft per US roll |
| 12″ | 8-12% | 24 sq ft per US roll |
| 18″ | 12-18% | 23 sq ft per US roll |
| 24″+ | 15-22% | 21 sq ft per US roll |
Subtractions:
- Standard door: count as 0.5 strip width (saves ~half a strip)
- Standard window: count as 0.5 strip width
- Don't subtract small windows — you still need a full strip on each side
Common Mistakes:
- Ignoring pattern repeat — the biggest source of under-ordering; a 24" repeat can reduce usable yield by 22%
- Confusing single rolls and double rolls — US pricing is per single roll but packaging is in double-roll bolts
- Ordering from multiple dye lots — color varies noticeably between runs
- Not ordering 1-2 extra rolls — damage during installation, future repairs, and miscalculation are common
- Wallpapering over textured walls without skim coating — bubbles and pattern distortion are guaranteed
Frequently Asked Questions
How many rolls of wallpaper do I need for a room?
A 12×14 ft room with 9 ft ceilings has roughly 52 ft of perimeter. At 20.5" wide strips, that's about 30 strips. With a standard pattern repeat, expect 3-4 usable strips per double roll, so you need 8-10 double rolls. Always buy 1-2 extra rolls.
How much does wallpaper cost per roll?
Budget wallpaper: $20-40 per double roll. Mid-range designer: $40-100. Premium/luxury: $100-300+. For a typical 12×14 room needing 8-10 rolls, total cost is $160-800 for paper alone. Adhesive, tools, and primer add $30-60.
What is wallpaper pattern repeat?
Pattern repeat is the vertical distance before the design repeats itself. A 24" repeat means every 24 inches, the pattern starts over. When hanging strips side by side, you must align the pattern at the seam — the leftover at top and bottom is waste. Larger repeats = more waste.
How do I wallpaper around doors and windows?
Hang a full strip over the opening, then use a sharp blade to cut around the frame. This ensures pattern alignment on both sides. You'll waste the material behind the door/window, but the visible pattern will match. The calculator accounts for this — partial subtractions, not full strip eliminations.
Can I wallpaper over existing wallpaper?
Not recommended. Old wallpaper may bubble, peel, or show texture through new paper. Remove old wallpaper with a scoring tool and removal solution ($15-25), skim coat any damage, then prime with wallpaper primer before hanging new paper. Proper prep takes longer but lasts years longer.
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