Wall Square Footage Calculator
Calculate the total wall area of any room. Enter your wall dimensions and openings to get accurate material estimates for painting, wallpapering, or paneling.
Sum of all wall lengths around the room
How do I calculate the square footage of a wall?
Multiply the wall height by the wall length. For multiple walls, calculate each separately and add them together. Subtract openings (doors: ~21 sq ft each, windows: ~15 sq ft each) for net wall area. Example: A 10 ft wide by 8 ft high wall = 80 sq ft. A room with four 8 ft walls totaling 120 ft length × 8 ft height = 960 sq ft total before openings.
How much paint do I need for my walls?
One gallon of paint covers approximately 350-400 sq ft of smooth surface. Calculate total wall square footage, subtract openings, then divide by coverage. For a 400 sq ft room: Two coats need about 2.5 gallons. Porous surfaces or drastic color changes may need more. Always buy slightly more than calculated for touch-ups.
Should I measure wall area including trim and baseboards?
For paint calculations, include trim if painting it the same color. For wallpaper, exclude trim as it is not covered. For estimating materials, trim area is usually negligible (about 5-10% of wall area). Most calculators work with total wall area minus major openings.
How do I measure irregular walls or vaulted ceilings?
Break irregular walls into rectangles and triangles. For vaulted ceilings, measure from floor to peak at the wall center. Calculate rectangular section (width × standard height) plus triangular section (0.5 × width × height above standard). Add both for total wall area. Sloped walls under 3 ft height are often considered unusable space.
Do I subtract windows and doors from wall square footage?
Yes, subtract standard openings for accurate material estimates. Standard door: 21 sq ft (3 ft × 7 ft). Standard window: 15 sq ft (3 ft × 5 ft). Larger openings like sliding glass doors: 42 sq ft (6 ft × 7 ft). Skip subtracting openings for small trim work calculations.