Circumference Calculator

Circumference Calculator

Measurement Used To Find Circumference:
Enter in Measurement:
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Circumference Formula:

If Area is used = sqrt(Measurement/3.14159265)*(2*3.14159265)
If Diameter is used = Measurement*3.14159265

Circumference Definition

The circumference is a distance measurement that shows the length of the line that creates the outside of the circle. One simple way to find the circumference is to use a string and wrap it around a round object. The point where the string overlaps itself should be marked. When you straighten out the string, measure between the marked point and the end of the string to find the circumference.

Why You Need To Know the Circumference

Knowing this distance around a circle can be very useful in many situations. These include:

  • Basic math problems
  • Calculating building materials for a round space
  • Finding the distance around a circular pond or water garden
  • Finding how far a wheel moves with each turn
  • Calculating the distance around a circular track or path

Information Needed for This Calculator

To use this calculator, you will need one of two measurements about the circle in question. These are:

  • Area: This is the measurement of the area of the inside of the circle in square units.
  • Diameter: This is the greatest distance between two points on the circle.

The units used for measuring either the area or the diameter will be the same as the circumference. For instance, if you input 2 inches for the diameter, the circumference will be in inches, or if you use 3 centimeters squared for the area, the circumference measurement will be in centimeters.

Formulas for Circumference

Since you put one of two pieces of information into the circumference calculator, there are two ways to calculate circumference. If you use the diameter of a circle, the calculator uses the formula that multiplies diameter by the number pi, which equals approximately 3.14. If you use the area, the calculator divides the area by pi and takes the square root of that answer to find the circle’s radius, which is half the diameter. Doubling this number and multiplying it by pi is how the circle’s circumference is found.

Check out some of our the other math calculators on the site

How to Calculate Circumference

Let's be honest - sometimes the best circumference calculator is the one that is easy to use and doesn't require us to even know what the circumference formula is in the first place! But if you want to know the exact formula for calculating circumference then please check out the "Formula" box above.

Add a Free Circumference Calculator Widget to Your Site!

You can get a free online circumference calculator for your website and you don't even have to download the circumference calculator - you can just copy and paste! The circumference calculator exactly as you see it above is 100% free for you to use. If you want to customize the colors, size, and more to better fit your site, then pricing starts at just $29.99 for a one time purchase. Click the "Customize" button above to learn more!