Circle Calculator

Enter any one value (radius, diameter, circumference, or area) to automatically calculate all other circle properties.

Input Values

Enter any one property of a circle.

Circle Visualization

r

Formulas

Circle calculation formulas reference

Diameter (d = 2r)d = 2r
Circumference (C = 2πr)C = 2πr
Area (A = πr²)A = πr²

Circle Properties

The radius is the distance from the center to the edge of the circle. The diameter is a line segment passing through the center, twice the radius. Circumference is the total length of the circle's edge, and area is the space enclosed by the circle. π (pi) is the circle constant, approximately 3.14159.