Wallpaper Calculator: Free Online Wallpaper Calculator

Use this wallpaper calculator to work out how many rolls you need for a room or accent wall. It's meant for DIY decorators and paperhangers pricing a job before ordering. Enter your total wall area (openings already subtracted) and the coverage of the roll you've picked, and it returns both single-roll and double-roll counts so you can order the right way your supplier sells it.

How to use this calculator.

1. Measure each wall. Multiply wall height by width for every wall you're papering, then add the areas together.
2. Subtract doors and windows. Subtract the area of each opening from your total: a standard door is about 21 sq ft, a typical window about 15 sq ft.
3. Enter the net wall area. Type the result into the calculator above.
4. Enter the roll coverage. Check the label: American single rolls typically cover 28-36 sq ft after trimming; large pattern repeats push actual usable coverage toward the low end.
5. Review your results. The calculator shows single rolls needed and the equivalent in double rolls, since most wallpaper is sold as a double roll at retail.

How do you calculate wallpaper rolls needed?

The calculator divides your net wall area by how much a single roll covers, then halves that figure to get double rolls.

Single Rolls Needed = Wall Area ÷ Roll Coverage

Double Rolls Needed = Single Rolls Needed ÷ 2

Where:

• Wall Area: Total square footage of wall to be papered, with door and window openings already subtracted.
• Roll Coverage: Usable square footage per single roll after trimming and pattern matching, typically 28-36 sq ft.

Example calculation.

Scenario: You're wallpapering an accent wall and two adjoining walls in a bedroom. After measuring and subtracting a door and two windows, your net wall area comes to 390 sq ft. You've chosen a paper with usable coverage of 30 sq ft per single roll.

1. Calculate single rolls: 390 sq ft ÷ 30 sq ft = 13 single rolls
2. Convert to double rolls: 13 ÷ 2 = 6.5, round up to 7 double rolls

Result: Order 13 single rolls(7 double rolls) to complete the job with a little left over for mistakes.

Tips from the field.

• Buy all rolls from the same dye lot. Color varies batch to batch; mismatched lots show up as visible seams once hung.
• Large pattern repeats waste more paper. A 24-inch repeat can add 15-20% waste versus a random-match paper: budget extra rolls accordingly.
• Round up to the next full roll. Partial rolls aren't sold, and running one strip short mid-wall means a delayed reorder.
• Prime and size the wall first. Bare drywall pulls paste unevenly; a wallpaper primer/sizing coat improves adhesion and makes future removal easier.
• Keep one spare roll after the job. Store it unopened for future repairs, since discontinued patterns are common and hard to match years later.
• Peel-and-stick paper covers less per roll. Removable vinyl wallpaper is typically sold in narrower rolls than traditional pasted paper: check the actual coverage on the label rather than assuming the 28-36 sq ft range applies.

Note that grasscloth, mural panels, and other specialty wallpapers are usually sold and measured differently than standard rolls: check the manufacturer's coverage chart directly rather than relying on this calculator's roll-based math. For a straightforward papered room with a standard American roll, though, the formula above gets you a reliable order quantity.

Disclaimer: This calculator provides estimates for planning purposes only. Actual roll counts vary based on pattern repeat, wall layout, and installer waste. PavementCalculator.com assumes no liability for material overages or shortages.