# Circumference of a Circle

**Formula:**`C = 2 × π × r`

## Introduction to Circumference of a Circle Calculator

The circumference of a circle is calculated by multiplying its radius by 2 and then by π. In this formula, ** C** represents the circumference of the circle, and

**is the radius of the circle. The result is expressed in the same units as the radius.**

*r*## Parameter usage:

`radius`

= radius of the circle

## Example valid values:

`radius`

= 5

## Output:

`circumference`

= circumference of the circle

## Data validation

The number should be greater than or equal to zero.

## Summary

This calculator takes into account the radius of a circle and outputs its circumference. It is not specific to a particular unit of measurement.

Tags: Geometry, Circle, Circumference