Circle Circumference Calculator
Enter a radius or diameter to calculate the circumference of a circle.
Result will appear here.
| Metric | Value |
|---|
Uses C = 2πr or C = πd.
Privacy: calculations run locally in your browser. No values are stored or transmitted.
How it works
Radius input: C = 2πr
Diameter input: C = πd
Examples
- radius = 5 → circumference ≈ 31.42
- diameter = 10 → circumference ≈ 31.42
FAQ
- What is the formula for circle circumference?
Circumference = 2πr or πd.
- Can I enter diameter instead of radius?
Yes. This calculator lets you choose radius or diameter as the input type.
- What is circumference?
Circumference is the distance around the circle.
- Are my values stored?
No. Calculations run locally in your browser and are not stored or transmitted.