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🖼️ Wallpaper Calculator

Enter your room dimensions and wallpaper roll size to find exactly how many rolls you need - with allowances for pattern repeat waste and door/window deductions.

🖼️ Enter Room & Roll Details

Rolls Needed
0

Details

0 sq ft
Total Wall Area
0 sq ft
Coverage Per Roll
0
Strips Needed

How Wallpaper Rolls Are Calculated

Total Wall Area

Wall Area = Room Perimeter × Wall Height
(minus door/window area if subtracting)

Usable Strip Length (with pattern repeat)

Usable Length per Strip = Roll Length − (Pattern Repeat waste allowance)

Strips & Rolls Needed

Strips per Wall Height = Roll Length ÷ Wall Height (rounded down)
Total Strips Needed = Room Perimeter ÷ Roll Width
Rolls Needed = Total Strips ÷ Strips per Roll (rounded up)

Always Round Up

Wallpaper is sold in full rolls, and it's standard practice to order at least 10% extra for cutting waste, mistakes, and future repairs.

Frequently Asked Questions

Calculate your total wall area (perimeter × height), subtract door and window area, then divide by the usable area per roll (roll length × roll width, minus a pattern repeat waste allowance). Standard US rolls are typically 27 inches wide by 27 feet long (double rolls are common), while European rolls are often 21 inches wide by 33 feet long - always check the specific roll size on your chosen wallpaper before ordering.
Patterned wallpaper needs to align at the seams between strips, which means some material is cut away and wasted at the top or bottom of each strip to match the pattern. A larger pattern repeat (the vertical distance before a pattern repeats) wastes more material - a 24-inch repeat wastes noticeably more than a small 6-inch repeat. Solid or non-patterned wallpaper needs little to no extra allowance.
Yes, for accurate estimates, but many installers still recommend keeping a small buffer since wallpaper is typically sold in full rolls (you can't buy a fraction of a roll), and offcuts from around doors and windows are often not large enough to reuse elsewhere. This calculator lets you optionally subtract door and window area, but it's wise to round up rather than order the exact minimum.

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Wallpaper Calculator - Find How Many Rolls You Need

Ordering wallpaper without an accurate estimate risks either running short mid-project (and struggling to match dye lots later) or over-ordering expensive material. This calculator uses your room's perimeter and wall height, along with your specific roll dimensions and pattern repeat, to estimate exactly how many rolls to buy.

Standard US roll: 27 in wide × 27 ft long (double roll)  ·  Standard European roll: 21 in wide × 33 ft long

Why Pattern Repeat Matters

Wallpaper with a repeating pattern needs to line up at the seams between adjacent strips. To achieve this, installers must offset where they start cutting each strip, which wastes some material at the top or bottom. A large pattern repeat (say, 24 inches) wastes noticeably more paper than a small one (6 inches) or no repeat at all. Always check the pattern repeat measurement listed on your chosen wallpaper - it's usually printed on the label or product page.

Tips for Ordering Wallpaper

  • Order 10-15% extra: Covers cutting mistakes, odd-shaped walls, and future repairs without needing to reorder (and risk a different dye lot).
  • Buy all rolls from the same dye lot/batch: Color can vary slightly between production runs - check the batch number on each roll before purchasing.
  • Measure each wall separately if the room is irregular: This calculator assumes a rectangular room using total perimeter; complex layouts (alcoves, bay windows) benefit from wall-by-wall measurement.
  • Keep leftover rolls: Store any extra, unopened rolls for future repairs - matching wallpaper years later can be difficult or impossible if a pattern is discontinued.

How this calculator works, and where the numbers come from

The Wallpaper Calculator applies the standard formula for this calculation to the values you enter and updates the result as you type. The calculation itself happens in your browser, and the page explains the method so you can check any result by hand.

Please note: Results are estimates. Add allowance for waste and check product labels and local building codes before you buy or build.

Sources and further reading

Learn more

Read our guide: How Much Paint, Flooring and Concrete Do You Actually Need?

Last reviewed: by the CalcQube Editorial Team. See our editorial policy for how we build and check calculators, or report an error.