Input Values

Result

Select an input type, enter a value, and click Calculate.

About Circle Calculations

A circle is a perfect round shape where all points are equidistant from the center. Key formulas:

  • Diameter: d = 2r
  • Circumference: C = 2πr = πd
  • Area: A = πr²

Where r is the radius, d is the diameter, C is the circumference, and A is the area.

Note: π ≈ 3.14159265359

Plane Geometry Calculators