Formula and Assumptions
Net wall area = perimeter x height - door area - window area.
Actual conditions, local rates, product labels, and contractor recommendations can change the final quantity or cost.
Example Calculation
A 14 x 12 x 8 ft room with two doors and three windows has about 326 net sq ft.
Tips
- Measure large windows separately.
- Do not subtract tiny openings.
- Use primer for patched walls.
FAQ
Can I change door and window sizes?
Yes, enter the average square footage for each opening.
Does this include trim?
No, trim is usually estimated separately.
Can this estimate paint cost?
Use the paint cost calculator for cost.
Why subtract openings?
Large openings reduce paintable wall area and can reduce gallons needed.