Wallpaper Calculator
How much wallpaper do you need? Enter your room size and roll type.
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Wall area—
Estimated cost—
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How this calculator works
It measures your wall area (room perimeter × wall height) and adds 15% for pattern matching and trimming, then divides by the usable coverage of one roll.
Worked example — a 12 ft × 12 ft room, 8 ft walls, single rolls:
Perimeter 48 × 8 = 384 sq ft × 1.15 = 442 ÷ 25 = 18 rolls.
Patterns need more
Big repeating patterns waste more at each seam. For a large pattern repeat, bump your order up by another roll or two.
Frequently asked questions
How much wallpaper do I need for one room?
Measure the wall area and divide by the roll’s usable coverage — most single rolls cover about 25 sq ft after trimming.
Should I buy single or double rolls?
Double rolls have fewer seams and less waste on tall walls, but single rolls are easier to handle.
Planning a wall or paint project
Surface condition matters as much as area. Rough, porous, repaired, or strongly colored surfaces may need extra primer or paint. Check the coverage printed on the product you plan to use and account for trim, ceilings, openings, and a second coat where applicable.
How to use this estimate
- Measure the project in the units shown and recheck your measurements before ordering.
- Use the waste allowance as a planning buffer, not as a substitute for a detailed material takeoff.
- Compare the result with the package yield, coverage, or weight listed by your supplier.
- Prices are user-entered estimates and may change by location, product, delivery, and season.
Accuracy and limitations
Calculapedia provides educational planning estimates. It does not inspect your site, select products, guarantee quantities, or replace a contractor, engineer, architect, building official, or supplier. Confirm the final quantity and any safety or code requirements before buying or building.