Calculate the area of common 2D shapes with formula display
This area calculator supports seven common 2D shapes: square, rectangle, circle, triangle, trapezoid, parallelogram, and ellipse. Select a shape, enter the required dimensions, and choose your preferred unit to get the area in square units with the matching formula displayed.
Area measures the space inside a 2D shape in square units, while perimeter measures the distance around the outside of the shape in linear units.
The formula is derived by dividing a circle into many small triangles and rearranging them into a rectangle of width πr and height r. As the number of triangles approaches infinity, the area approaches πr².