A percent circle, also known as a pie chart or a circle graph, is a chart shaped like a circle. It is divided into segments, much like a pie, to show percentages or sizes of parts that make up a whole, also known as proportional relationships. Percent circles are used when values can be added together or when there's only one data series with all values being positive.
Components of a Percent Circle

Percent circles are made up of segments, with the amount of segments varying depending on the number of factors being compared. Percent circles can have detailed information by inserting data into each segment in the circle or directly beside the segment outside the circle. Sometimes, a legend is created as a reference. The different segments in a pie chart are usually filled in using different colors to represent each segment to make it easier to read. Take into consideration that percent circles are not able to represent values that exceed 100 percent.
When to Use Percent Circles

A percent circle allows you to visualize the sizes of specific sections of a whole. They are best used when comparing groups that are related to each other. For example, a percent circle can be used to show different types of beverages sold by a store, different ingredients used in a recipe, or the percentage of athletes in a particular competition. Additionally, percent circles can be used to compare two different things such as the percentage of male and female students in a school.
What Percent Circles Are Not Used

Percent circles don't give detailed information as other charts may. Percent circles are not ideal for use when comparing exact values because estimating angles rather than distance may be difficult for some. Ranked data is also not best interpreted using a percent circle. Bar charts are easier for comparison of this kind of data because most compare more than one value, and they can be compared side by side. Percent circles are also not the best choice when comparing values with proportions that vary greatly. Additionally, percent circles should not be used to show how values increase or decrease over time or to show direct relationships between numbers when the numbers rely on each other.
Creating a Percent Circle

The first thing that you need to create a percent circle is data. This data is used to show the proportion of each category as a part of the whole. Data can be in percentages, numbers or even currency depending on the information being compared. Of course, the size of the segments in the circle should correspond with the number for that segment. For example, a segment that shows 45 percent should be larger than a segment showing 20 percent.
Other Types of Percent Circles

An exploded percent circle is another type of percent circle. It shows the contribution of each value of a total with emphasis on different values. A pie of pie chart is a type of percent circle that extracts some values from the main circle and combines them into a second circle. It is used to make small percentages easier to read or to emphasize a group of values.