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Switch tool with the current settings for radius, and calculate circle area, circle diameter, sphere volume or sphere surface area instead

## Related Tools

- Calculate radius of circle from circumference
- Circle area calculator using radius
- Circle diameter calculator using radius
- Length and distance converter
- Sphere volume calculator using radius
- Sphere radius to surface area calculator

## User Guide

This tool will calculate the circumference of a circle from the radius, and will convert different measurement units for radius and circumference.

### Formula

The formula used to calculate circle circumference is:

C = 2 · π · r

#### Symbols

- C = Circle circumference
- π = Pi = 3.14159…
- r = Circle radius

### Radius of Circle

Enter the radius of a circle. The radius is the distance between the centre and any point on the outer edge of a circle.

### Circumference of Circle

This is the total length of the edge around the circle with the specified radius, if it was straightened out.