Wallpaper Calculator
Estimate the number of wallpaper rolls you need, accounting for pattern repeat and waste.
Wallpaper Calculator
Getting Your Wallpaper Order Right (So You Don't Run Short)
Measuring for wallpaper is straightforward: room perimeter times ceiling height equals wall area. A 12×12 room is 48 feet of perimeter. At 8 feet tall, that's 384 square feet of wall. Subtract door and window openings (but honestly, small windows don't save you much material). Then account for pattern matching waste, which is where people mess up.
Standard Wallpaper Roll Sizes (It Varies by Region)
| Type | Width | Length | Coverage | Where |
|---|---|---|---|---|
| Single (American) | 20.5" | 33 ft | ~56 sq ft | USA, Canada |
| Double (American) | 20.5" | 66 ft | ~112 sq ft | USA, Canada |
| Single (American) | 27" | 33 ft | ~75 sq ft | USA (European) |
| Single (European) | 21–27" | 33 ft | ~48–63 sq ft | Europe |
Pattern Repeat: The Thing That Kills Your Estimate
Wallpaper patterns need to match at seams—that's non-negotiable. If your wallpaper has a 12-inch repeating pattern, you're going to lose inches from every strip to make the pattern line up right. Large bold patterns waste 20–30% of material. Small geometric or solid colors? Almost no waste.
Waste Factors You Actually Need to Use
Solid or no pattern? Add 0–10%. Small repeats (under 6")? 10%. Medium repeats (6–12")? 15%. Big bold patterns? 25% or more. You're covering up visible waste, corners need matching, and alignment takes material. Buy extra. One extra roll is way cheaper than running short and having to reorder a different dye lot that doesn't match.
Accent Walls (Less Paper, Less Money)
Just one wall? Calculate only that wall's area. A 12-foot wall at 8 feet tall is 96 square feet. Using 27" rolls (75 sq ft coverage), you need 96 ÷ 75 = 1.28 rolls. Buy 2 rolls to account for pattern matching and a mistake buffer.
Peel-and-Stick vs. Traditional (The DIY Revolution)
Peel-and-stick changed everything. No adhesive, no mess, removable without damage to walls. Rolls are smaller (usually 28" × 10–20 feet), so coverage is different. Calculate the same way but use the actual roll dimensions. Installation is way more forgiving, so waste is lower than traditional—maybe 10% instead of 15%. You're doing this yourself anyway, so stick with peel-and-stick unless you want professional-looking seams and you're keeping it forever.
Corners and Openings (Where Things Get Tricky)
Corners need pattern matching and careful cutting—add 5–10% extra for rooms with lots of turns. Doors and windows? Subtract them from your area, but don't expect to save much. A small bathroom window doesn't give you enough material back to matter. Large openings (like a sliding glass door) do matter, so subtract carefully.
Real Example: 12×12 Room with 1 Door and 1 Window
Perimeter (12+12+12+12) × 8 feet high = 384 sq ft. Door opening 3×7 = 21 sq ft. Window 3×4 = 12 sq ft. Usable wall = 384 – 21 – 12 = 351 sq ft. Using 27" rolls (75 sq ft each): 351 ÷ 75 = 4.68 rolls. Add 15% for pattern matching: 4.68 × 1.15 = 5.38. Buy 6 rolls. At $25 a roll, that's $150 plus installation.
When You Order (Details Matter)
Get all rolls with the same dye lot (batch number) printed on the back. Different batches look slightly different due to manufacturing variations. Have rolls delivered a few days early so they acclimate to the room's temperature and humidity. Store them standing up in the tube until you're ready to install.
