Circle Radius Calculator - Calculate Circle Radius

How to Calculate Circle Radius

You can calculate the radius of a circle using the following information:

1. If the diameter (d) is available in the data, you can calculate the radius using the following formula:
   Radius = Diameter / 2
2. If the circumference (C) value is available, you can calculate the radius using the formula:
   Radius = Circumference / (2 × π)
3. If the area (A) value is available, you can calculate the radius using the formula:
   Radius = √(Area / π)

Calculator features:

• The radius appears instantly when you type the diameter, circumference or area.
• A drawing of your circle labels the radius, diameter, circumference and area together.
• The circumference is shown unrolled into a straight line to show it equals π × the diameter.