Circle
Calculate a circle’s diameter, circumference, and area from its radius.
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Use one consistent length unit. Circumference is 2πr and area is πr². Area uses the square of your chosen unit. Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.
Your result
How to use Circle
- Enter the values you want to calculate and choose the relevant units or settings.
- The result updates as you type. Adjust the available settings if needed.
- Review the result, then use Copy result or a download link when available.
What to expect
Calculate a circle’s diameter, circumference, and area from its radius. Use one consistent length unit. Circumference is 2πr and area is πr². Area uses the square of your chosen unit.