Square Footage Calculator
Calculate the square footage of a room, home, or space with this easy area calculator. Enter length and width to quickly determine total area. This tool is useful for flooring, real estate, painting, and renovation projects.
Dimensions
Total Area
Enter dimensions to calculate square footage.
How to Measure Square Footage
Square footage (area) is calculated as Length × Width for rectangular spaces. For a room that is 14 feet long and 12 feet wide, the area is 168 square feet. Measure in feet — if your tape measure shows inches, divide by 12 first. For an L-shaped room, divide it into two rectangles, calculate each area, and add them together. For triangular areas, use 0.5 × Base × Height. For circular areas, use π × radius² (π ≈ 3.14159).
Always measure along the longest walls, including any closets or alcoves that will need flooring or paint. Take measurements twice from different starting points to catch errors. Round up to the nearest foot for material estimates — it is better to order slightly more than to come up short mid-project when dye lots may differ.
Square Footage for Real Estate vs. Construction
Real estate square footage typically measures interior living space — bedrooms, bathrooms, kitchen, and living areas. It usually excludes garages, unfinished basements, and attics. Methods vary by state and listing service, so two homes listed at 1,800 sq ft may measure differently. For construction and remodeling, you measure the actual floor area to be worked on — wall to wall, including under furniture and in closets. For flooring or painting materials, this is the number you need, not the real estate listing figure.
Frequently Asked Questions
How do I measure an irregular or non-rectangular room?
Break the room into simple shapes — rectangles, triangles, or semicircles. Calculate the area of each shape separately, then add all the areas together. For a room with a bay window bump-out, measure the main rectangle and the bump-out rectangle separately and sum them. For slanted ceilings or walls that are not perfectly perpendicular, use the floor dimensions (since that is what you are covering), measuring wall-to-wall across the floor even if the ceiling angles inward above.
How much extra square footage should I order for flooring?
Standard recommendation is 10% extra for waste, cuts, and pattern matching. For diagonal installations, add 15%. For rooms with many angles or cut-outs (like around a fireplace or columns), add 15–20%. For tile specifically, add 10% for standard layouts and 15–20% for diagonal or offset patterns. Extra material also gives you a reserve for future repairs — matching the exact tile or flooring product years later can be difficult if the pattern or dye lot is discontinued.
How do I convert square feet to square yards (for carpet)?
Divide square feet by 9. There are 9 square feet in a square yard (3 ft × 3 ft = 9 sq ft). A 200 sq ft room needs about 22.2 square yards of carpet. Carpet is often sold by the square yard, though many retailers now list prices in both. When comparing carpet prices, check which unit is being used — $15/sq yd looks like a bargain until you realize the competitor's $2.50/sq ft price is actually cheaper ($22.50/sq yd equivalent).
How to Use This Calculator
- Measure the length and width of the room or area in feet. For inches, divide by 12 first (e.g., 186 inches ÷ 12 = 15.5 feet).
- Enter both measurements into the calculator.
- Click Calculate to see the total area in square feet.
- For flooring or paint, add a 10% waste allowance to the result before ordering materials.
For irregular rooms, split the space into rectangles, calculate each area separately, and add the totals together.
Worked Example
You are installing hardwood flooring in a living room and want to know how much to order.
Room length
18 feet
Room width
14 feet
Area (18 × 14)
252 sq ft
With 10% waste allowance
252 × 1.10 = 277.2 sq ft
Disclaimer: Results are estimates based on the dimensions entered. Actual material quantities depend on room shape, waste from cuts, and installation method. Always verify measurements and consult with a flooring or construction professional before purchasing materials.