What Is the Circle Area Calculator?
This calculator finds the area of a circle from its radius using the classic formula A = π r^{2}. A circle is the set of all points equidistant from a center point, and that distance is the radius (r). Knowing the area is useful for everything from designing round tables and pizzas to engineering pipes, gardens, and landscaping projects.
How to Use It
Enter the radius of your circle in any unit you like (centimeters, meters, inches, feet). The calculator returns the area in those units squared, along with the diameter (2r) and circumference (2πr) for convenience. If you only know the diameter, simply divide it by two to get the radius first.
The Formula Explained
The area formula is
Worked Example
Suppose a circle has a radius of 5 units. Then
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