Online calculator. Circumference of a circle (perimeter of a circle)

This free online calculator will help you to find the circumference of a circle.

Using this online calculator, you will receive a detailed step-by-step solution to your problem, which will help you understand the algorithm how to find circle circumference.

Calculator

Guide

Some theory

Calculation of circumference of a circle

Select defined data

Input length of circle radius :

r =

Entering data into the circumference of a circle calculator

You can input only integer numbers or fractions in this online calculator. More in-depth information read at these rules.

N.B. In online calculator you can use the value in the same units of measurement!

If you have any difficulties with units conversion, you can use the length converter.

Theory. Circumference of a circle

Circle

is a simple shape consisting of those points in a plane that are equidistant from a given point, the centre. The distance between any of the points and the centre is called the radius.

The formulas for circumference of a circle

P = 2 π r

P = π d

where P - circumference of a circle (perimeter of a circle),
r - circle radius,
d - circle diameter,
π = 3.141592.

You can input only integer numbers, decimals or fractions in this online calculator (-2.4, 5/7, ...). More in-depth information read at these rules.