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

## Related Tools

- Calculate radius of circle from diameter
- Circle area calculator using radius
- Circle circumference 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 diameter of a circle from the radius, and will convert different measurement units for radius and diameter.

### Formula

The formula used to calculate circle diameter is:

ø = 2 · r

#### Symbols

- ø = Circle diameter
- 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.

### Diameter of Circle

This is the diameter of a circle that corresponds to the specified radius. The diameter of a circle is the length of a straight line drawn between two points on a circle where the line also passes through the centre of a circle, or any two points on the circle as long as they are exactly 180 degrees apart.