The circumference of a circle is the distance around the outside of the circle. It could be called the perimeter of the circle. It is very useful to know how to find the circumference of a circle will come in handy in a variety of circle-related problems.

## How to Calculate the circumference of a circle

There are two ways to find the circumference.

### 1) Using the Diameter

**C = πd **is the formula for finding the circumference of a circle using the diameter. “C” represents the circumference of the circle, and “d” represents its diameter.

### 2) Using the Radius

**C = 2πr** is the formula for finding the circumference of a circle using the radius. In this formula, “r” represents the radius of the circle.