Circumference calculator
The following circumference calculator is easy to use.
Just enter the value of the radius and hit calculate button.
Recall that the formula to get the
circumference of a circle
is 2 ×pi×r with pi = 3.141592653589793
Therefore, the circumference depends only on the size of r. That is why you only need to enter r here to get the circumference.
The calculator will only accept positive value for r since a distance cannot be negative.
As a reminder, if r = 4 cm for instance,
circumference = 2 ×3.14 ×4 = 25.12 cm
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