CalculateConverter.com

Circle Calculator

Enter a single known value (radius, diameter, area, or circumference) and we will instantly calculate the rest.

Circle Calculator

Enter any one known value to find the rest.

Circle Properties

Radius (r) Diameter Circumference

Formulas:

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

A circle is perfectly symmetrical. Knowing just a single measurement allows you to uncover every other property of the circle using the mathematical constant Pi (π ≈ 3.14159).