Circle Calculator

All tools

Enter any one of radius, diameter, circumference or area and instantly compute all the other circle properties. Free, accurate and easy to use.

r
Area –
Radius –
Diameter –
Circumference –
Area –
Calculations use π (pi). Diameter = 2r, circumference = 2πr and area = πr². Results are in the same unit as your input (area is squared).
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