This geometry calculator will take one known circle measurement (area, circumference, diameter, or radius) and calculate the other three.

Plus, unlike other online circle calculators, this calculator will show its work and give a detailed, step-by-step explanation of the formulas and sequence used to arrive at each result.

For your convenience, the calculator also includes 4 mini calculators you can access by tapping the plus (+) icon on each circle measurement line ...

- Circle Area Calculator
- Circumference Calculator
- Diameter Calculator
- Radius Calculator

... and 2 conversion calculators for converting between tape measurements (feet/inches) and decimal numbers (one button appears at the top of the calculator and the other appears at the bottom).

If you are unfamiliar with the common measurements used in plane circle geometry, it may help to visit the Learn tab to learn about them before using the calculator.

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