Wall Square Footage Calculator

Your details

Choose the unit your tape measure uses. All outputs convert automatically.
The longer floor dimension of the room.
ft
The shorter floor dimension of the room.
ft
Floor-to-ceiling height. Standard US ceilings are 8 or 9 ft.
ft
Each standard interior door subtracts about 20 sq ft from the paintable area.
doors
Each standard residential window subtracts about 12 sq ft.
windows
Two coats give full, even coverage. One coat works for touch-ups over a matching color.
Add the ceiling area to the paint and primer totals.
Enter your paint price per gallon for a total material cost estimate. Leave at 0 to skip.
USD
Enter price per 4x8 sheet (32 sq ft) for a drywall material cost estimate. Leave at 0 to skip.
USD
Net wall area
424sq ft

Total paintable or coverable wall area after subtracting doors and windows

Gross wall area468sq ft
Opening deductions44sq ft
Ceiling area168sq ft
Paint needed2.42gal
Primer needed1.41gal
Drywall sheets (4x8)17sheets

Net wall area: 424 sq ft, paint needed: 2.4 gal

  • Your net paintable wall area is 424 sq ft after removing 44 sq ft for doors and windows (9% of gross).
  • For 2 coats, buy 3 gallons of paint and 2 gallons of primer.
  • You need 17 sheets of 4x8 drywall (includes 10% for cuts and waste).

Next stepAdd 10-15% extra to your paint order to match existing paint later and cover inevitable touch-ups. Always buy from the same production batch (lot number) for consistent color.

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