Circumference Calculator

No. Enter just one measurement. If you provide the radius, the calculator uses C = 2 pi r. If you provide the diameter, it uses C = pi d. Either value is sufficient to compute circumference.

The calculator uses the full-precision value of pi (3.14159265358979...) built into the computing engine, giving you accuracy to many decimal places.

Circumference is the specific term for the perimeter of a circle. Both words mean the total distance around a shape, but circumference applies only to circles and ellipses.

First calculate the radius from the area using r = sqrt(A / pi), then use C = 2 pi r. For example, if the area is 78.54, the radius is 5, and the circumference is 31.4159.

Yes. Enter the outer diameter of a pipe, wheel, or any circular object to find how far around it measures. This is commonly used in plumbing, automotive, and manufacturing contexts.

You can. Look for the "Embed" button near the top of this calculator. It lets you pick a size, border style, and color palette, then gives you an iframe tag to paste into any webpage. The widget is responsive, loads fast, and costs nothing. More details at calculory.com/services/embed-calculators.