Calculate the area of circles, rectangles, triangles, and other shapes with formulas and step-by-step solutions.
Not needed for circle or square
Enter values above to see results
Rectangle: A = l × w | Circle: A = π × r² | Triangle: A = ½ × b × hAAreal, wLength and width (rectangle)rRadius (circle)b, hBase and height (triangle)πPi ≈ 3.14159265Area measures the two-dimensional space enclosed by a shape. Each geometric shape has its own formula derived from its unique properties. The circle formula uses pi because the ratio of a circle's circumference to its diameter is always π.
Geometry is the branch of mathematics concerned with shapes, sizes, and properties of figures. The area calculator is an essential tool for students, architects, engineers, interior designers, and anyone who needs to measure two-dimensional space. From calculating the floor area of a room to determining the size of a garden, area calculations are ubiquitous in both academic and professional settings.
Select your shape from the dropdown menu, enter the required dimensions, and the calculator instantly computes the area and perimeter using the appropriate geometric formula. The step-by-step breakdown shows each calculation clearly, making it easy to understand and verify the result.
This calculator supports five common shapes - rectangle, circle, triangle, square, and trapezoid - covering the vast majority of real-world area calculation needs. It eliminates the need to memorize multiple formulas and reduces the risk of arithmetic errors.
A frequent mistake is confusing radius and diameter when calculating circle area. The formula uses radius (half the diameter), so if you know the diameter, divide it by 2 first. For triangles, ensure you are using the perpendicular height, not the slant height.
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