Circle Calculator
Calculate area, circumference, radius, and diameter of a circle.
Circle Calculator
Results
Radius (r):
Diameter (d):
Circumference (C):
Area (A):
How to Use
- Enter one known value (Radius, Diameter, Circumference, or Area).
- The other values will be calculated automatically.
About Circles
A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre.
Formulas
Diameter = 2 * Radius Circumference = 2 * π * Radius Area = π * Radius^2
Features
- Calculate all properties from one input
- High precision using π
Applications
- Engineering
- Architecture
- Design