Circle Circumference Calculator

Calculate the circumference of a circle quickly and easily! Just enter the radius, select your unit, and get instant, accurate results.

Enter Radius:

Select Unit:

Result:

Calculation Steps:

Understanding Circle Circumference

The circumference of a circle is the distance around its edge. It's essentially the perimeter of a circle.

The formula to calculate the circumference (C) is given by: $$ C = 2\pi r $$ where r is the radius of the circle (distance from the center to any point on the circle's edge), and $$\pi$$ (pi) is a constant approximately equal to 3.14159.

Example: For a circle with a radius of 5 cm, the circumference is: $$ C = 2 \times \pi \times 5 \approx 31.42 cm $$

This calculator simplifies finding the circumference. Just input the radius and select the unit for quick and accurate results! It's useful for geometry problems, construction, and various real-world applications.