# Circumference of a Circle Calculator

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

This circumference of a circle calculator will figure out the circumference of any circle given the radius, the diameter, 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 Circumference of a Circle Using Radius

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

C = 2 ϖ r

where

C = Circumference
ϖ = Pi = 3.14159265...

### Calculating the Circumference of a Circle Using Diameter

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

C = ϖ d

where

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

### Calculating the Circumference of a Circle Using Area

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

where

C = Circumference
A = Area
ϖ = Pi = 3.14159265...