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Wallpaper calculator

a 16 × 12 ft room at 8 ft with one 20 ft² door and one 15 ft² window is 413 ft² of net wall. A 56 ft² single roll with 15% waste rounds to 9 rolls. In metric, net wall area is 38.37 m².

Formula. (2 × (L + W) × H − openings) × (1 + waste) ÷ roll coverage

Single-roll count from room perimeter, ceiling height, opening deductions and the usable coverage printed on the roll.

By Feroz Sheikh · Formula PNT-WLP-001 v1.0.0 · Tested formula

FormulaPNT-WLP-001v1.0.0

Project inputs

Enter your measurements. Switching units converts the same project, including coverage and unit rates. Package yields keep the unit printed beside each field.

Room lengthft + inFinished room lengthftinRoom widthft + inFinished room widthftinCeiling heightft + inFinished floor-to-ceiling heightftinDoorscountDoor openings to deductWindowscountWindow openings to deductDoor deductionft²Editable area deducted per doorWindow deductionft²Editable area deducted per windowCoverage per rollft²US single roll is often 56 ft² on the label; pattern match sits in waste, not a smaller rollWaste factor%Allowance for pattern match, repeats and trimming. 15% is a common patterned-paper planning figure

Refine measurements and rates at any time. Your current values are included in the material-list PDF.

Calculated result

9rolls

Rolls to buy

FormulaPNT-WLP-001

(2 × (L + W) × H − openings) × (1 + waste) ÷ roll coverage

413 ft²

Net wall area

474.95 ft²

Area including waste

56 ft²

Coverage per roll

Planning estimate, not engineering advice. Confirm site measurements and product specifications. Calculation limits.

Wallpaper: measurement diagram. Room walls use perimeter and height; ceiling area uses length and width. Check the opening and ceiling options. — Room walls use perimeter and height; ceiling area uses length and width. Check the opening and ceiling options. View image

Use finished room length, width and ceiling height to get net wall area after door and window deductions, then divide by the coverage printed on the wallpaper roll and apply a visible pattern-match allowance before whole-roll rounding.

Measure the room, not the roll. Perimeter times height is the starting wall area.
Deduct the actual door and window openings, or leave the planning defaults if you have not measured them yet.
Enter the label coverage of the roll you will buy. Raise waste for a large pattern repeat instead of shrinking the roll.

Add your project costs

Enter supplier prices and any labour, equipment or delivery costs. Pick a currency — badges, inputs, and totals follow.

Costs use the can rate you type. Construclytic does not fetch paint prices. Primer, ceiling gallons and cut-and-roll labour stay on their own lines. For GCC projects, select QAR, AED, SAR, KWD, OMR or BHD and enter local supplier rates.

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How this calculator works

A transparent wallpaper takeoff.

Feroz SheikhWritten and reviewed by Feroz Sheikh · founderFormula PNT-WLP-001 v1.0.0 automated checks Nov 3, 2026.

PNT-WLP-001 counts single rolls from room perimeter, ceiling height, opening deductions and the usable coverage after pattern repeat. Paint gallons do not convert to rolls. Formula ID stays on the sheet.

Worked example. Example: a 16 × 12 ft room at 8 ft with one 20 ft² door and one 15 ft² window is 413 ft² of net wall. A 56 ft² single roll with 15% waste rounds to 9 rolls.

See the example inputs and calculated result

This separate example uses the calculator's starting values in imperial units. It stays unchanged when you edit the tool above. Example rates, yields and dimensions are assumptions, not recommendations for your project.

Wallpaper: example inputs
Input	Example value
Room length	16 ft
Room width	12 ft
Ceiling height	8 ft
Doors	1 count
Windows	1 count
Door deduction	20 ft²
Window deduction	15 ft²
Coverage per roll	56 ft²
Waste factor	15 %

Example result: Rolls to buy — 9 rolls.

(2 × (L + W) × H − openings) × (1 + waste) ÷ roll coverage

Use the labelled units above when reproducing this example. To work in metric, switch the calculator to Metric; applicable measurements are converted, while product-specific units remain labelled.

1. Measure the room, not the roll. Perimeter times height is the starting wall area.
2. Deduct the actual door and window openings, or leave the planning defaults if you have not measured them yet.
3. Enter the label coverage of the roll you will buy. Raise waste for a large pattern repeat instead of shrinking the roll.

Field notes that change the number

Pattern repeat eats coverage. Enter the usable yield, not the roll’s raw ft².
Dye lots should be one batch — round up rather than shorting a wall.
Paste and liner are extras.

Common mistakes

Using paint coverage as wallpaper rolls.
Ignoring pattern repeat.
Treating this as a mural layout.

Need the broader workflow? Read the painting planning guide.

Questions

Questions about wallpaper

Is 56 ft² the usable coverage?

It is the common US single-roll label area. Pattern match, wrapping corners and trimming the ceiling line all sit in the waste field. A 15% allowance is planning, not a guarantee.

Double rolls?

If the merchant sells double rolls, double the coverage per roll (often about 112 ft²) so the count stays in the unit you will buy.

What is the formula ID?

This wallpaper calculator publishes formula PNT-WLP-001, version 1.0.0. The ID stays on the result and on the estimate line.