Square Footage Calculator
Calculate room or property square footage from dimensions
Formula
Multiplies the length by width of a rectangular space. For irregular shapes, divide into rectangles and sum the areas.
Examples
20×15 living room
20 × 15 = 300 sq ft = 27.9 m²
3-bedroom apartment
Measure each room and add together, or use average room size × number of rooms.
50×100 lot
5,000 sq ft = 0.115 acres = 464.5 m²
Frequently Asked Questions
About Square Footage
The Square Footage Calculator helps you determine the area of rooms, properties, lots, and spaces by multiplying length times width. Square footage is the standard measurement for real estate, construction, flooring, painting, and rental pricing in the United States.
Knowing your square footage is essential for: buying or selling a home (price per square foot is the key comparison metric), ordering flooring materials (hardwood, tile, carpet), estimating paint quantities, planning furniture layouts, calculating heating/cooling capacity (HVAC sizing), determining rental prices, and estimating renovation costs.
For rectangular rooms, simply multiply length × width. For irregular shapes, divide the space into rectangles, calculate each area, and sum them. For triangular areas, use ½ × base × height. For circular areas, use π × radius². Most rooms can be broken down into combinations of these basic shapes.
Key conversions: 1 square foot = 0.0929 square meters; 1 square meter = 10.764 square feet; 9 square feet = 1 square yard; 43,560 square feet = 1 acre. International real estate typically uses square meters.
When measuring for real estate listings, follow the ANSI standard: measure from exterior walls for single-family homes, from interior walls for condos. Include all finished, heated living space. Exclude garages, unfinished basements, patios, and porches. Attic space counts only if it has at least 7-foot ceiling height and is finished.
Cost estimation: renovation costs vary widely by location and scope. National averages range from