Wall Square Footage Calculator

Calculating the square footage of walls is essential for estimating materials like paint, wallpaper, or paneling. The process involves finding the total area of the walls and then subtracting the areas of any openings like windows and doors.

1. Measure Each Wall: For each wall section, measure the Length (in feet) and Height (in feet).
2. Calculate Gross Area: Multiply the Length by the Height for each wall section (`Area = Length × Height`). Sum the areas of all wall sections to get the Total Gross Wall Area.
3. Measure Openings: Measure the Width (in feet) and Height (in feet) of each window, door, or other large opening that won't be covered.
4. Calculate Deduction Area: Multiply the Width by the Height for each opening (`Area = Width × Height`). Sum the areas of all openings to get the Total Deduction Area.
5. Calculate Net Area: Subtract the Total Deduction Area from the Total Gross Wall Area: `Net Wall Area = Total Gross Wall Area - Total Deduction Area`. This is the final square footage you need to cover.

• Use a Metal Tape Measure: Provides more accuracy than cloth tapes.
• Measure Twice: Double-check your measurements to avoid errors.
• Round Up Slightly: When measuring, rounding up to the nearest inch or half-inch can provide a small buffer.
• Sketch Your Room: Drawing a simple diagram can help visualize the walls and ensure you don't miss any sections or openings.
• Measure Wall Height Consistently: Measure floor to ceiling in a couple of places per wall, especially if you suspect variations. Use the tallest measurement if unsure or average if variations are minor.
• Complex Shapes: Break down L-shaped rooms or walls with alcoves into simple rectangular sections and measure each one.

The "Net Wall Area" calculated is the key figure for estimating materials:

• Paint: Most paint cans list their coverage per gallon (e.g., 350-400 sq ft). Divide the Net Wall Area by the paint's coverage rate to estimate the number of gallons needed per coat. Remember to account for multiple coats.
• Wallpaper: Wallpaper rolls specify their square footage coverage. Divide the Net Wall Area by the roll's coverage. You'll likely need to add a waste factor (15-20%) for pattern matching and trimming.
• Other Coverings: For paneling, tile, or other materials, use the Net Wall Area to determine the quantity based on the coverage per unit or box of the specific product.

Always add a small percentage for waste (cutting, mistakes) to your final material calculation, especially for paint and wallpaper.