Circle Calculator
Math ToolsRadius, diameter, circumference and area
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History
All history →Circle Calculator — at a glance
Radius, diameter, circumference and area.
Your text or values
Run
Instant result
How to use it — step by step
Just your input — nothing to install or sign up for.
1
Enter your values
Fill in the boxes. Sample values are already there so you can see how it works.
2
Calculate
Press the button to get your answer instantly.
3
Read the result
The main answer is shown in a large card with extra details below it.
4
Copy it
Use the copy button to save the result anywhere.
Pro tips
Small things that make the result better.
✦Circumference = 2πr and Area = πr².
✦π is used as 3.14159265…
Quick facts
Freeno signup, no limit
Instantresult in a moment
Privatenothing is uploaded
Any devicephone, tablet or PC
Frequently Asked Questions
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
Is this tool really free?+
Yes — completely free, no signup, no watermark and no usage limit.
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