The Circumference of a Circle formula, C = 2πr, computes Circle the circumference (perimeter) of a circle as a function of the radius (r).
INSTRUCTIONS: Choose units, and enter the following:
Circumference (C): The calculator returns the circumference (perimeter) of the circle in meters. However, this can be automatically converted to other length units via the pull-down menu.
The formula for the circumference or perimeter of a circle is: