Trade Math · Square Feet
Calculating total square feet
Area shows up whenever you're ordering flooring, figuring tile, or sizing a roof patch. The formulas are short; the mistakes are where points go. Here's the rectangle, the triangle, the circle, and how to handle the composite shapes that make up real rooms. Locals vary. Check your local's test format.
Cheat sheet
- Rectangle: Area = L × W
- Triangle: Area = (1/2) × base × height
- Circle: Area = π × r² (π ≈ 3.14)
- Composite shapes: split into sub-rectangles and add, OR start from the bounding rectangle and subtract what's missing.
- Unit conversion: 1 sq ft = 144 sq in (12 inches × 12 inches).