Calculate Area of Circles & Properties

If you want to find the area (A), circumference (C), radius (r) and diameter (d) of any circular shape, then enter one of the input properties, and our circle calculator tool will work out the other values.

The formula to find the area and circumference of a circle is shown below:

Area = πr2

Circumference = 2πr

Radius (r)
Diameter (d)
Area (A)
Circumference (C)

*Radius, diameter, circumference will be in units (e.g. metres), and area will be in unit squares (e.g. metre2)