Area Calculator
Compute area for rectangles, circles, triangles, and more.
Area Calculator
What This Calculator Does
The Area Calculator computes surface area for four common construction shapes: rectangles, circles, triangles, and trapezoids. Each shape uses its own formula - the calculator handles the math so you don't have to remember which formula applies to which project.
Construction and landscaping projects rarely come in perfect rectangles. Patios have curved edges, yards are trapezoidal, and roof sections are triangular. Using the wrong formula or approximating by eye leads to material shortages or overages that cost both time and money. This calculator gives you the area for each shape type in square feet, the standard US construction unit.
Select your shape, enter the required dimensions, and get the area, plus conversion to square yards. For rectangles, you need length and width. For circles, enter the radius. For triangles, provide base and height. For trapezoids, enter both bases and the height.
How to Use
- Select the shape that matches your project from the dropdown: Rectangle, Circle, Triangle, or Trapezoid.
- Enter the required dimensions for your selected shape in feet.
- Click "Calculate" to get the area in square feet and square yards.
- Use "Copy Result" to save your area for use with material calculators on this site.
- For complex projects combining multiple shapes, calculate each shape separately and add the results.
Reference Table
| Shape | Formula | Example Dimensions | Area (sq ft) |
|---|---|---|---|
| Rectangle | L x W | 20 x 30 ft | 600 sq ft |
| Circle | pi x r squared | Radius = 10 ft | 314 sq ft |
| Triangle | 1/2 x b x h | Base 20 x Height 15 ft | 150 sq ft |
| Trapezoid | 1/2 x (b1 + b2) x h | Bases 20+30 x Height 12 ft | 300 sq ft |
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