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Tools City

Circumference Calculator

Find the Circumference of the circle by using Tools City's free online Circumference Calculator. The circumference of a circle is the outside distance around the circle. It's similar to the perimeter of other forms, such as squares.

Base and height triangle image
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Explain the Circumference of any Circle?

The distance of the length around the boundary of a circle is said to be the circumference of a circle. It is comparable to the perimeter of other forms, such as squares. We may think of it as the shape's defining line. 

We can let it be known this way that the external lines of shapes made of straight edges are called edges, and for circles, this characterizing line is known as the circle's boundary.

The circumference of a circle is the length of its line. Allow us to open a circle and measure the boundary like a straight line. We can determine the circumference of a circle in terms of different units such as centimeters, meters, kilometers, etc.

The three most significant features of a circle are mentioned below.

  • Center: A center is a spot that is at a particular space from any other point on the circle.
  • Diameter: The diameter of any circle is the length from the origin points to the circumference of the circle.
  • Radius: The radius of any circle is the distance between the center point of any circle and the point along its perimeter.

For example,

A boy ran from point 'A' on the ground and covered a distance while completing a round of it. The distance he covered of the boundary wall will be known as the 'circumference' of the ground.

How you can figure out the value for the circumference of a Circle?

The formula to measure the circumference of a circle by radius is:

Circumference = 2 x pi x radius

C = 2 π r
where:

  • 'C' symbolizes the circumference of a circle
  • 'Pi' (π) shows a constant ratio of the circumference
  • 'r' symbolizes the radius of a circle

However, if you do not know the value of the radius, you can determine it with the help of Diameter

Radius = Diameter/2

r = d/2 or R = D/2.

This formula can also be used to derive the diameter of a circle:-

d = 2 x r or D = 2 x r

Which formula is used to calculate the area of the circle?

Following are the formulae used for figuring out the values for the area of a circle and the perimeter of a circle.

Area = pi x square of the radius or
A= π
r2

where:

  • A is called the circle's area.
  • Pi (π) is the ratio of the circumference whose value is 3.142. 
  • r is considered as the radius of a circle

How to use Tools City's Circumference Calculator?

On the Tools City's Circumference Calculator these are the options displayed:

  • Radius (r)
  • Diameter
  • Circumference (c)
  • Area

Simply enter the value of the unit which is already known and the tool will automatically show the results for the other three within a few milliseconds.

Circumference Calculator also provides the facility of changing the unit of your measurement into the below-mentioned units:

  • millimeters (mm)
  • centimeters (cm)
  • meters (m)
  • kilometers (km)
  • inches (in)
  • feet (ft)
  • yards (yd)
  • miles (mi)

How to do it manually?

We are also here to help you derive the values manually by yourself. It is very easy for you to find out the values for the circumference of a circle and the area of the circle.

Example 1: 

If the radius of a ring is 8 mm. Find its circumference and the area.

As we know the radius is 8 mm:-

Using the formula for:

  • Diameter of a circle

D = 2R = 2*8 ≈ 16 mm

  • Circumference of a circle

C = 2πr = 2*3.14*8 ≈ 50.26 mm

  • Area of a Circle

A = πR2 = 3.14 *(8)2
A = 3.14 * 64 
A ≈ 201.06 mm2 

Example 2: 

If the diameter of a circle is 12 m. Calculate its circumference and the area.

As we know the diameter is 12 m:-

Using the formula for:

  • The radius of a circle

R = D/2 = 12/2 ≈ 6 m

  • Circumference of a circle

C = 2πR = 2*3.14*6 ≈ 37.69 m

  • Area of a Circle

A = πR2 = 3.14 *(6)2

A = 3.14 * 36

A ≈ 113.09 m