Shape area calculator

Calculate the area of a rectangle, triangle or circle.

Your numbers

Both a decimal point and a comma work.

Result

20 m²

Area

Perimeter: 18 m

How it works

S = a × b

Using the calculator

Enter «Rectangle»: Length · Width. Calculation: S = a × b.

Enter «Triangle»: Base · Height. Calculation: S = b × h / 2.

Enter «Circle»: Radius. Calculation: S = π × r².

Worked input and result

Example (Rectangle): Length = 7 m; Width = 3 m. Result: Area = 21 m² (Perimeter: 20 m).

Example (Triangle): Base = 8 m; Height = 5 m. Result: Area = 20 m².

Example (Circle): Radius = 3 m. Result: Area = 28.274334 m² (Perimeter: 18.849556 m).

Understanding the result

Enter all dimensions in metres. Triangle height is perpendicular to its base. A circle’s radius is half its diameter.

Choose the shape that matches your measurements. For a circle, the entered radius is half the diameter; for a triangle, height is perpendicular to the chosen base.