Circumference to Diameter Calculator

Convert the circumference of a circle to the diameter or vice-versa using our conversion calculator below.

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How to Convert the Circumference of a Circle to the Diameter

A circle is a round, symmetrical shape where each point along its edge is equidistant from the center point. A circle has several properties that define its size, including its circumference and diameter.

The circumference is the distance around the outside edge, also known as its perimeter.

The diameter is the length of a straight line from one edge to the opposite edge that passes through the circle’s center. The diameter is equal to twice the length of the radius.

diagram of a circle showing the radius, diameter, and circumference
Diagram showing the circumference and diameter of a circle

You may need to find one of the properties using the information you know about the circle using a formula. If you know the circumference, you can find the diameter using one of these formulas.

Circumference to Diameter Formula

Given the circumference of a circle, you can find the diameter using the following formula:

d = C/π

The diameter d is equal to the circumference C divided by pi. You can also find this answer using our circle calculator.

For example, let’s calculate the diameter of a circle with a circumference of 5.

d = 5/π = 1.59

Thus, this circle has a diameter of 1.59.

How to Find the Circumference Using the Diameter

You can find the circumference of a circle given the diameter using a similar formula:

C = πd

The circumference C is equal to pi times the diameter d. You can also use our circumference calculator to find this answer.

For example, let’s calculate the circumference of a circle with a diameter of 7.

C = π × 7 = 21.99

So, the circumference of this circle is equal to 21.99.