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Wall Area Calculator

Calculate the total wall area of a room for painting, wallpapering, or paneling. Subtract doors and windows.

Room Dimensions

Wall Area Results

Net Wall Area

330sq ft

Net Wall Area (Metric)

30.66m²
Detailed Material Breakdown
Gross Wall Area (No Deductions)
396 sq ft
Deductions (Doors & Windows)
66 sq ft

Calculation Formula & Assumptions

Calculates the gross and net surface area of room walls by multiplying room perimeter by height and deducting doors, windows, and fireplace openings.

Net Area = [2 × (Length + Width) × Height] − Openings

Step-by-step breakdown:

  • Perimeter = 2 × (Room Length + Room Width)
  • Gross Area = Perimeter × Wall Height
  • Openings Area = (Doors × Door Height × Door Width) + (Windows × Window Height × Window Width)
  • Net Area = Gross Area − Openings Area

Note: Essential preparatory calculation for painting, wallpaper, wood paneling, or insulating.

Worked Calculation Example

Home Office Wall Area

Measuring a 10×12 ft office with 9 ft ceilings, one entrance door, one closet door, and one window.

Dimensions:10 ft × 12 ft × 9 ft high
Doors:2 doors @ 3×7 ft (42 sq ft)
Windows:1 window @ 4×5 ft (20 sq ft)
Calculation Steps:
  1. Perimeter = (10 + 12) × 2 = 44 ft
  2. Gross Area = 44 × 9 = 396 sq ft
  3. Deductions = 42 + 20 = 62 sq ft
  4. Net Wall Area = 396 − 62 = 334 sq ft (31.03 sq meters)
Net paintable/coverable wall area is 334 sq ft.

How to Use This Calculator

  1. Enter room length and width in feet or meters.
  2. Enter wall height.
  3. Specify count and dimensions of doors and windows.

Common Estimation Mistakes to Avoid

  • Measuring wall height from top of baseboard rather than finished floor level.
  • Deducting electrical outlets or vents (too small to deduct).

Frequently Asked Questions

No. Baseboards and casing represent a tiny fraction of area. Leaving them in the calculation provides a safe buffer for cut waste.

Related Project Guides

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How to Calculate Paint for a Room: A Practical Guide

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How to Measure Wall Area for Painting, Wallpaper & Paneling

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