Square Footage Calculator
Area of rooms, lots and odd shapesRuns in your browser
Split the space into rectangles, triangles and circles; the areas are added up.
Rough material cost
$504Enter any price per square foot (flooring, sod, paint job, installation quote) to get a total.
Material estimates only. Round up, buy a little extra, and check with your supplier. Structural work (footings, framing, roofs) must follow local building codes; consult a licensed contractor where required.
How it works
Formulas
Rectangle = length × widthTriangle = base × height ÷ 2Circle = π × (diameter ÷ 2)²1 sq yd = 9 sq ft; 1 m² = 10.764 sq ft; 1 acre = 43,560 sq ftWorked example
Input: An L-shaped room: 12 × 10 ft plus a 6 × 4 ft alcove.
- 12 × 10 = 120 sq ft.
- 6 × 4 = 24 sq ft.
- 120 + 24 = 144 sq ft = 16 sq yd = 13.38 m².
Result: 144 square feet.
Limits
- Measure wall to wall at floor level. For a home's official living area, appraisers follow ANSI Z765 rules (finished, heated space only).
How to use
- 1Split the space into simple shapes: an L-shaped room is two rectangles.
- 2Enter each shape's measurements in feet (or meters); add as many areas as you need.
- 3Add a waste allowance if you are buying material.
- 4Read the total in square feet, square meters, square yards and acres, and enter a price per square foot for a cost.
FAQ
How do I calculate square footage?
Multiply length by width in feet. A 12 × 10 ft room is 120 sq ft. For odd shapes, split them into rectangles, triangles (base × height ÷ 2) and circles (π × radius²) and add them up.
How do I measure an L-shaped room?
Divide it into two rectangles that do not overlap, measure each, and add the areas. A 12 × 10 ft room with a 6 × 4 ft alcove is 120 + 24 = 144 sq ft.
How many square feet are in an acre?
43,560 square feet. A square acre is about 208.7 ft on each side.
How do I convert square feet to square meters?
Divide by 10.764. 144 sq ft is 13.38 m².