# Circumference Calculator

## Introduction to Circumference Calculator

The circumference is the distance around the outside of the circle denoted by (C). It is also called the perimeter of the circle. Circumference calculator allows you to calculate diameter, area & circumference online.

If you know the value of (r), circumfrence formula to calculate circumference will be:

$$C\;=\;2πr$$

As we know the value of pi is fixed for all circles.

If you know the value of (d), the formula for circumference will be

$$C\;=\;πd$$

## Formula used by Circumference Calculator

The distance around a circle is known as the circumference. The circumference of a circle calculator uses this circumference formula

$$C\;=\;2πr$$

The radius is half the distance of a diameter denoted by (r).

$$r\;=\;\frac{d}{2}$$

Circumference and rotations calculator also computes the area of a circumference. It uses the same formula for finding those results.

$$r\;=\;\frac{C}{(*2)}$$

Suppose the circumference of a circle is 20cm, you want to find the radius. Put the value into the equation.

$$r\;=\;\frac{C}{(*2)}$$ $$r=\frac{20}{(3.14*2)}=3.18cm$$

By following this way a circumference formula calculator works to find out the radius of a circle.

Circumference basically deals with arc length. Find arc length solver to calculate queries by making few clicks.

## What is Diameter?

The diameter is the distance across the center of a circle denoted by (d). If you know the radius of a circle, you can calculate the diameter by multiplying the radius by 2. Circumference of a circle calculator allows you to calculate diameter digitally without any problem.

$$d = 2 * r$$

If you don't know the radius, you can calculate diameter by dividing the circumference by pi.

$$d\;=\;\frac{c}{π}$$

If you don’t know circumference or radius of a circle, you can find the diameter by dividing the area by pi and after that find the square root of that number to get the radius.

## What is Pi?

Pi is the ratio of circumference to its diameter of a circle. The value of this ratio is 3.14156. This value is true for all circles.

$$π=\frac{C}{d}$$

## How to calculate Circumference of a Circle?

You can use circumference formula calculator to solve circumference online. For manual calculations, let's assume we draw a circle of radius 3.5 centimeters. It will look something like this. As we know this blue boundary of the circle will be its perimeter. The perimeter of the circle is also called circumference.

But how can we measure the circumference of the circle? The circumference is round and the scale is used to measure any straight length. It is very simple. Have a look at given below method or visit on circumference tutorial. Find the circumference of the above-given circle, the radius is 3.5 cm.

## How to calculate Circumference with Circumference formula?

To avoid manual calculations one can use circumference formula calculator to get equation for circumference solved quickly, For manual calculations, process is below mentioned.

Circumference of circle = 2πr

While π = 3.14

By putting values C = 2 * 3.14 * 3.5

$$C\;=\;22cm$$

So, in this case, when we are given the radius, we can calculate circumference by above-given circumference formula. But if there is given diameter, the circumference formula will be:

$$Circumference\;=\;πd\;\;$$ $$d\;=\;diameter$$

By putting value C = 3.14 * 7

$$C\;=\;22cm$$

As we can find circumference from diameter, likewise, we can find diameter if we are known circumference.

### Example

Circumference problem

The diameter of a wheel is 40 cm. How many complete rotations will denote the distance of 1km?

As

$$C\;=\;d$$

While

$$π\;=\;3.14$$

By putting the values into formula

$$C\;=\;3.14 * 40$$ $$C\;=\;126 cm$$

While 1km = 100,000

Number of complete rotation = 100,000 / 126

$$=\;794km$$

Also find pythagorean theorem calculator for claculating the length of sides of right angle triangle.

## Circumference to Diameter Calculator

As you might have noticed that the diameter is 2 times longer than the radius, and the circumference and diameter is dependent on each other in a circle. So,

$$C/D=2πr/2r=π$$

$$\frac{C}{D}\;=\;\frac{2πr}{2r}\;=\;π$$

This equation of diameter to circumference is also a definition of the constant. It is also used in finding cone volume.

## How to use Circumference Calculator?

Circumference formula calculator is simple and very easy to use. To calculate the circumference of a circle, just provide radius to our circumference calculator and get your answer. Our circumference to diameter calculator will show you diameter, circumference & area as the results.

We hope you liked our circumference calculator and its theory. You can also find other useful calculators on our portal, but don't forget to provide us your valuable feedback. Cheers!

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### Alan Walker

Last updated: September 09, 2020

Studies mathematics sciences, and Technology. Tech geek and a content writer. Wikipedia addict who wants to know everything. Loves traveling, nature, reading. Math and Technology have done their part, and now it's the time for us to get benefits.