**What is the Perimeter of a circle?** The **perimeter of a circle**, also known as the **circumference**, is the distance around the edge of the circle. It is the length of the circle’s outer edge. The formula to calculate the circumference of a circle is** C = 2Ï€r** where C is the circumference and r is the radius of the circle.

For example, if the radius of a circle is 5 units, the circumference would be 2Ï€(5) = 2 * 3.14 * 5 = 31.4 units.

It’s worth noting that the **diameter **of a circle is just 2 times the radius, so one could also use the formula **C = Ï€d instead of C = 2Ï€r** where d is the **diameter **of the circle.