Circumference Calculator & Formula

Use this circumference calculator when you need to solve for different kinds of geometry exercises. This circumference to diameter calculator is specifically created to help you find the circumference, diameter, and area of a circle. In this article, you’ll learn how to use the calculator, how to calculate circumference manually using the circumference formula, and more.

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How to use the circumference calculator?

This circumference calculator is simple and extremely easy to use. You can use it to find the diameter to circumference when faced with geometric problems. The great thing about this online tool is that it’s very easy to understand and it provides you with instant answers. Here are the steps to follow for this circumference to diameter calculator:

  • First, enter the value of the Radius and choose the unit of measurement from the drop-down menu.
  • Then enter the value of the Diameter and choose the unit of measurement from the drop-down menu.
  • After entering both values, the circumference calculator automatically generates for you the values of the Circumference and the Area.

How do I calculate circumference?

You can use this calculator to find the diameter to circumference for different applications. Whether you plan to do craft work, you plan to put a fence around a hot tub, you need to solve a math problem for school or for whatever reason, knowing how to solve for the circumference of a circle comes in handy.

As long as you’re faced with circle-related problems, this circumference calculator and the circumference formula will help you out. If you want to solve for circumference by hand, here are some steps for you:

  • First, write down the circumference formula using when you have the value of the radius. The value of the radius of a circle is half of the value of its diameter. Therefore, you can think of the diameter as 2r.
  • Keeping this concept in mind, you can start writing the formula down for solving for the circumference of the circle when you have the radius:

    C = 2πr

    In this equation, r refers to the radius of a circle, while π refers to the value of pi. You can use a calculator to get the numerical value of pi which is approximately 3.14.

  • When you have all of the values you need, you can use these into the formula and start solving. To help illustrate this better, let’s use an example. Let’s say, for instance, you want to cut out a decorative strip of paper which you’ll wrap around a freshly-baked pie.
    For this example, let’s assume that your pie has a radius of 5-inches. In order to solve for the circumference you need, plug the values into the formula. Here’s a rundown of how your solution may go:

C = 2πr
C = 2π x 5
C = 10π
C = 31.4 inches

As you can see, solving for circumference is very simple. Let’s work with another example. This time, let’s try to solve for the circumference when the value of the radius is 14 cm. Since you already have the radius value, you can substitute this in the formula:

C = 2*π*R
C = 2*π*14
C = 87.9646 cm

Therefore, the circumference for this example is 87.9646 cm. Apart from the circumference, having the value of the radius also allows you to find the area of the circle. This time, you use a different formula:

A = π * R^2
A = π * 14^2
A = 615.752 cm2

Therefore, the area for this example is 615.752 cm2. Finally, you can also use the same values to find the diameter of the circle. This is the easiest value to find as it’s double the value of the radius:

D = 2*R
D = 2*14
D = 28 cm

Therefore, the diameter of this example is 28 cm. No matter what formula you use or what value you’re solving for, you can use the circumference calculator to check your answer and see if you performed the computations correctly.

What is the circumference formula?

The circumference of a circle refers to the linear distance of its edge. The circumference is the same value as the perimeter of any given geometric figure. However, the word “perimeter” is typically used for polygons only. In the previous section, we had gone through the steps to calculate the circumference.

To solve for this value, you need to use the circumference formula. This formula described the relationship between a circle’s radius and its circumference. The formula is:

C = 2πR

π refers to a constant value that’s approximately equal to 3.1416
R refers to the radius of the circle

How do you figure out circumference from diameter?

In some cases, you don’t have the value of the radius. Instead, you have to work with the value of the diameter. Therefore, you must also learn how to solve for the circumference given only this value. The formula for circumference using the diameter is, in fact, a lot simpler:

C = πd

In this formula, C refers to the circumference of the circle while d refers to the diameter of the circle. Simply put, you can solve for the circumference of a circle by multiplying the value of the diameter by the constant value of pi.

As aforementioned, plugging π into a calculator provides you with the constant’s numerical value which is approximately 22/7 or 3.1416. Let’s have another example to help you understand this formula and how to use it better.

Let’s say, for instance, that you have a circular tub with an 8-foot diameter. You would like to build a fence around this tub with a space that’s 6-feet wide. To solve for the circumference of this fence, you must first solve for the tub’s diameter along with the fence:

8 feet + 6 feet + 6 feet = 20 feet

This value accounts for the total diameter of the tub and the fence. Now use this value in the circumference formula:

C = πd
C = π x 20
C = 62.8 feet