# Diameter of a Circle Calculator

Want to calculate the diameter of a circle? Cool, try this calculator.

This diameter of a circle calculator will figure out the diameter of any circle given the circumference, the radius, or the area of the circle.

### Terminology

• "Area" - The amount of surface covered by a two dimensional shape. It is expressed in square units of measurement, for example square feet, square meters, square inches, square yards, etc.

• "Circumference" - The total distance around the outside edge of a circle.

• "Diameter" - The distance of a straight line that extends from edge to edge of the circle while passing through the center of the circle.

• "Radius" - The distance of a straight line that extends from the center of the circle to the edge of the circle.

### Calculating the Diameter of a Circle Using Circumference

If you know the circumference of a circle, you can calculate the diameter based on the following formula:

d = C / ϖ

where

C = Circumference
ϖ = Pi = 3.14159265...
d = Diameter

### Calculating the Diameter of a Circle Using Radius

If you know the radius of a circle, you can calculate the diameter based on the following formula. This one's easy, the diameter is always double the radius:

d = 2 r

where