FitAndFillSquare Footage Calculator: Area of Rooms and Shapes
Find the area of a rectangle, triangle, circle or trapezoid in square feet, square yards, square meters and square inches, from measurements in feet, inches, yards, meters or centimeters.
How the calculation works
rectangle = length × width triangle = ½ × base × height circle = π × (diameter ÷ 2)² trapezoid = ½ × (side 1 + side 2) × height Every measurement is first converted to feet (1 ft = 12 in = ⅓ yd = 0.3048 m), the area is calculated in square feet, and the other units come from that: 1 sq yd = 9 sq ft, 1 sq ft = 144 sq in and 1 sq ft = 0.09290304 sq m.
Worked example
A 12 × 10 ft room is 120 sq ft (13.33 sq yd, 11.15 sq m).
For an L-shaped space, split it into rectangles and add them. A 12 × 10 ft room plus a 6 × 4 ft alcove is 120 + 24 = 144 sq ft.
A round patio 10 ft across is π × 5² = 78.54 sq ft.
Assumptions and limits
- Shapes are flat and measured straight across. For an L-shaped or irregular area, split it into rectangles, triangles and circles and add the results.
- The result is the geometric area of what you measure. The square footage in a real estate listing, an appraisal or a tax record follows its own measuring rules and can differ.
- Closets, built-ins and other parts to leave out are not subtracted automatically: calculate them as shapes and subtract them.
- No allowance for waste is included; flooring, tile or sod need extra for cuts.
Frequently asked questions
How do I measure an L-shaped or irregular room?
Split it into rectangles, triangles and circles, calculate each part and add the results. To leave something out, such as a closet or a built-in, calculate it too and subtract it.
How do I convert square feet to square yards or square meters?
Divide square feet by 9 for square yards, and multiply by 0.09290304 for square meters. The results show all of them, plus square inches.
Is this the "square footage" of a home?
No. This tool calculates the geometric area of the shape you measure. The square footage in a real estate listing, an appraisal or a tax record follows its own measuring rules, so ask the person or office that produces it.
What if the measurements are in feet and inches?
Convert the inches to a fraction of a foot (divide by 12) and add them: 10 ft 6 in is 10.5 ft. Or enter everything in inches and read the result in square feet.
When do I use "How many"?
When you have several identical areas, such as four equal flower beds, calculate one and set "How many" to 4.
Do I need extra for waste?
This tool gives the exact area. Materials such as flooring, tile or sod need an allowance for cuts; use the matching calculator on this site or ask your supplier.
Sources
- NIST, "U.S. Survey Foot: Revised Unit Conversion Factors" (the international foot is defined exactly as 0.3048 m)
- Geometry: area of a rectangle (length × width), triangle (½ × base × height), circle (π × radius²) and trapezoid (½ × sum of the parallel sides × height)
- Unit definitions: 1 ft = 12 in; 1 yd = 3 ft; 1 sq yd = 9 sq ft; 1 sq ft = 144 sq in
Guides that help
- How to Measure Square Footage of a Room, Yard or Irregular Space
- Roof Pitch Explained: What 6/12 Means and How It Changes Your Shingle Count
- How Much Paint Do You Need for a Room: Walls, Doors, Coats and Coverage
- How Many Tiles Do You Need: Area, Grout Joints, Extra and Boxes
- How a Deck Is Counted: Boards, Joists and Fasteners
- How to Order Sod: Rolls, Slabs, Pallets and How Much Extra
More calculators
-
Tile Calculator
Work out how many tiles and boxes you need for a floor or wall from its size, the tile size, the grout joint and a waste allowance.
-
Paint Calculator
Work out how much paint a room needs from its size, doors, windows, number of coats and the coverage printed on the can.
-
Sod Calculator
Work out how many square feet, rolls or slabs and pallets of sod you need for a lawn, with an allowance for cuts and waste.