Wall Square Footage Calculator

The Wall Square Footage Calculator measures the total paintable or coverable wall area in a room — useful for estimating how much paint, wallpaper, or paneling you need before starting a project. Select your room shape, then enter your wall length, wall width, and ceiling height, along with the number of doors and windows and their dimensions. You'll get the total wall area (with openings subtracted), plus a breakdown of gross wall area, total door area, and total window area.

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Length of the wall or room

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Width of the room (for rectangle rooms)

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Combined length of all walls (for custom shapes)

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Results

Total Wall Area

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Gross Wall Area

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Total Door Area

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Total Window Area

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Frequently Asked Questions

How do I calculate wall square footage?

To calculate wall square footage, multiply the total wall length by the ceiling height to get gross area, then subtract the area of doors and windows. The formula is: Wall Area = (Wall Length × Height) - (Door Area + Window Area).

How many square feet is a 12x12 wall?

A 12-foot wide by 12-foot high wall has 144 square feet of area (12 × 12 = 144). However, you'll need to subtract any doors or windows to get the paintable area.

How many square feet is a 10x10 wall?

A 10-foot by 10-foot wall contains 100 square feet of surface area. Remember to account for doors, windows, or other openings that won't need paint or wallpaper.

Should I include doors and windows in wall square footage?

For painting or wallpapering, subtract door and window areas from your total wall area since you won't be covering these surfaces. This gives you the actual area that needs material.

How do I measure walls for a rectangular room?

For a rectangular room, measure the length and width, then calculate the perimeter: (Length + Width) × 2. Multiply this by ceiling height for total wall area, then subtract openings.

What's the standard door and window size for calculations?

Standard interior doors are typically 7 feet tall by 3 feet wide (21 sq ft). Standard windows vary but average around 3 feet by 4 feet (12 sq ft). Measure your specific openings for accuracy.

How much extra paint should I buy beyond calculated square footage?

It's recommended to buy 10-15% extra paint beyond your calculated wall area to account for waste, touch-ups, and future repairs. This ensures you have enough material and color matching.

Can I use this calculator for exterior walls?

Yes, this calculator works for both interior and exterior walls. For exterior walls, be sure to account for all windows, doors, and any architectural features that won't be painted or covered.