The circumference of the circle is the length of its boundary. Explore and learn to calculate the circumference of a circle, with concepts, definitions, formulas, solved examples, and practice problems. The circumference of a circle is equal to the length of its boundary, but the circle is a curved shape, its circumference can't be measured with a ruler. The correct way to find the perimeter of a circle is to calculate it using the formula C = 2π × r. Use this free circumference calculator to find the area, circumference and diameter of a circle. The Circumference Calculator helps you quickly determine the distance around a circle using either the radius or diameter. Whether you're working on a Geometry assignment, measuring materials, or handling design specifications, this tool offers a simple way to get accurate results across different units.
