Calculate radius, diameter, circumference, and area of a circle
Processed client-side in your browser — files never leave your device.
Free, with no signup, account, or usage limits.
Works on any modern browser, including mobile.
About this tool
Circle Calculator: Calculate radius, diameter, circumference, and area of a circle. Processing runs locally in your browser — your input is not uploaded to ThothBox.
How to use
Open Circle Calculator and enter the values you want to calculate or convert.
Adjust units or options if shown.
Read the result instantly.
Copy the output or try another set of inputs.
FAQ
What does Circle Calculator do?
Calculate radius, diameter, circumference, and area of a circle.
Is Circle Calculator private?
Yes for typical use: input is processed in your browser and is not uploaded to ThothBox.
Is Circle Calculator free?
Yes. It is free to use with no signup required.
How do I use Circle Calculator?
Open the Circle Calculator tool, then open Circle Calculator and enter the values you want to calculate or convert.