You can find many round things in everyday life. A mug, a wheel, a pipe, a lens are just a few examples. Sometimes you need to calculate the perimeter of a circle, or the circumference. You do not need to remember the formula, just go to this page and do all the calculations. Here you will find a simple and handy online circle perimeter calculator. To calculate, you need to know the radius or diameter of the circle.

## Formula for calculating the circumference

There are two formulas.

• P = 2πR, where R is the radius.
• P = πD, where D is the diameter.

In both cases, the number π is applied. Usually the decimal places are reduced to 3.14 and this is enough for most calculations. However, if you need to make more accurate calculations, then you can use 3.1415926535.

• Radius is the distance from the center to the edge of the circle. You can also calculate the radius by dividing the diameter in half.
• Diameter is the length of the segment passing through the center of the circle from one edge of the circle to the other. You can also calculate the diameter by doubling the radius.