An area calculator computes the two-dimensional surface area of common geometric shapes. It is used in construction, landscaping, flooring, painting and many other applications where you need to know the size of a flat surface. This calculator supports rectangles, squares, triangles and circles.

1. Select the shape.
2. Enter the required dimensions.
3. Select the unit of measurement.
4. Click Calculate.

Rectangle 5m × 3m = 15 m²
Circle radius 4m = π × 16 = 50.27 m²
Triangle base 6m, height 4m = 0.5 × 6 × 4 = 12 m²

For irregular shapes, divide them into simpler shapes (rectangles, triangles), calculate each area separately and add them together. For rooms with alcoves or recesses, calculate the total area and subtract the areas of any sections not to be covered.

• Using diameter instead of radius for circles — the radius is half the diameter.
• Using slant height instead of perpendicular height for triangles.
• Mixing units — ensure all dimensions are in the same unit.

How do I calculate the area of an L-shaped room?

Divide the L-shape into two rectangles, calculate each area separately and add them together.

What is the area of a circle with diameter 10m?

Radius = 10 ÷ 2 = 5m. Area = π × 5² = 78.54 m².