1. Measure wall dimensions
Measure height × width of each wall in feet.
What is wall square footage?
Wall square footage is the total wall area for paint, drywall, or paneling. Multiply wall height × width in feet for each wall. For walls with openings, use the wall with window calculator; for sloped or vaulted walls, the cathedral wall calculator.
Getting started
How to Calculate Wall Square Footage
To calculate wall square footage, measure height × width of each wall in feet. Multiply for individual wall area. Sum all walls for total. Subtract doors (21 sq ft) and windows (15 sq ft) for paintable area.
2. Sum all walls
Add the area of every wall for total wall square footage.
3. Apply material formula
Paint covers 350 sq ft per gallon. Drywall sheets cover 32 or 48 sq ft each.
Quick reference
Reference
1 acre = 43,560 square feet
1 square yard = 9 square feet
1 square meter = 10.764 square feet
1 square inch = 0.00064516 square feet
Material pricing
Calculate Cost of Materials
Interior paint costs $25-50 per gallon. Drywall sheets cost $10-15 each. Multiply wall area by price per unit for total cost.
There are 2 steps to calculate material cost:
- Enter the price per gallon of paint, per sheet of drywall, or per square foot of paneling.
- The Square Foot Calculator divides wall area by material coverage and multiplies by price for total cost.
Add 10% extra for cuts and waste. Primer and labor are sold separately.
Calculating Square Footage for Walls
Measure the wall width and the wall height in feet. Multiply the width by the height to get the total wall area in square feet. Subtract the area of any doors or windows to find the exact paint coverage required. A wall that is 12 feet wide and 8 feet tall has a total area of 96 sq ft. A 3 ft × 4 ft window removes 12 sq ft, leaving 84 sq ft of paintable surface.
To subtract multiple windows of the same size from one wall, multiply the window width by the number of windows. Enter the total as the window width in the Square Foot Calculator. Height remains the height of one window.
FAQ
Frequently Asked Questions
How do I calculate square footage of a wall?
Multiply wall height by wall width for total area, then subtract windows and doors. A 12x8 wall with a 3x4 window = 96 - 12 = 84 square feet of paintable area.
How much paint do I need for a wall?
One gallon of paint covers approximately 350-400 square feet. Calculate the wall square footage minus windows and doors, then divide by 350 for the number of gallons needed per coat.
How do I subtract multiple windows from wall area?
Calculate the area of each window and subtract from the total wall area. For identical windows, multiply one window's area by the number of windows.
Should I subtract doors from wall square footage?
Yes, subtract door areas when calculating paint or wallpaper needs. A standard door is about 3x7 feet (21 sq ft).
How do I calculate square footage for all walls in a room?
Calculate each wall separately and add the areas together. For a rectangular room, measure the two different wall lengths and multiply each by the ceiling height.
How many square feet of wallpaper do I need?
Calculate total wall area minus windows and doors, then add 10-15% for pattern matching waste. Wallpaper is typically sold in rolls covering 28-30 usable square feet.
REFERENCES
Further Reading & References
Trusted external sources and related sections on this site. External links open authoritative references on Wikipedia and government agencies.
Explore this Square Foot Calculator site
Authoritative external references
- WIKIWall — Wikipedia
- WIKIDrywall — Wikipedia
- WIKIInterior design — Wikipedia