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Pie chart

A pie chart visualizes a part-to-whole relationship. It shows how the data is divided into categories with a certain value (the slices), but it always keeps the link between the value of one category and the total sum of those categories (the pie).

This means that the slices should add up to a logical sum. If the data is in percentages, the total should round up to a hundred. If the data is in absolute values, for example in euros, the categories should form a meaningful total. 

This relative approach of comparing a part to a whole is key to understanding how to use a pie chart. If the focus of the visualization is on comparing values between categories, it’s better to use another chart type.

A pie chart works best with only a few categories, otherwise the chart becomes an unreadable clutter. It is also very suitable when one category is very big or very small compared to the other categories. But if the differences between the categories and thus between the slices are small and not easily recognizable, another chart - for example a bar chart - is much better suited.

A pie chart visualizes a part-to-whole relationship

Variations on a pie chart

The charts below are variations on a pie chart. To learn how to make them with Datylon, check out the pie chart user documentation in the Datylon Help Center.
A donut chart is one of the variations on a pie chart
A donut chart is one of the variations on a pie chart

Donut chart

Conceptually, the donut chart is equal to the pie chart, having the slices communicate the part-to-whole relation in the data.
Adding a hole in the center gives more room to add information like a description, a title or a total.

A semi circle pie or donut chart is a good alternative to a pie chart
A semi circle pie or donut chart is a good alternative to a pie chart

Semicircle pie/donut chart

This chart works the same as a normal pie or donut chart, only the sum of all categories results in half a circle instead of a full circle. It can serve as a basis for a gauge chart, by using the slices to show progress or by adding a pointer.

A nightingale chart does not communicate a part-to-whole relationship
A nightingale chart does not communicate a part-to-whole relationship

Nightingale chart

This chart is visually similar to a pie chart, but a Nightingale chart does not communicate a part-to-whole relationship. It compares values between categories, like a bar chart does, only this one is radial.

Alternatives for a pie chart

Substitute your pie chart with any of the charts below when you want a visual alternative, that still shows a part-to-whole relationship at a particular point in time.
A 100% stacked bar chart is a good alternative for a pie chart
A 100% stacked bar chart is a good alternative for a pie chart

100% Stacked bar chart

Instead of using slices, the 100% stacked bar chart (1 series) uses rectangles to draw the categories. This way, it’s easier to compare the size of the categories with each other.

A tree map is a good alternative for a pie chart
A tree map is a good alternative for a pie chart

Tree map

A tree map consists of a square or a rectangle that is proportionally divided into other rectangles, representing the categories. The size of the shapes represents the values.

An icon array is a good alternative for a pie chart
An icon array is a good alternative for a pie chart

Icon array

You can use icon arrays to communicate a part-to-whole relation by dividing a fixed amount of icons into groups and giving a color and/or shape to each category.

Pro tips for designing a pie chart

Learn how to improve the readability and visual appeal of your chart or graph
A pie chart has different coloring options

Coloring

There are different ways to color a pie chart. When using a legend, you can color categorically: every slice gets a distinct color and equals one category, but the hue of the colors needs to be different enough to easily switch your view from legend to pie chart. You can also give all slices the same color. That way only the size of the slice communicates the data. This results in a calmer and balanced look. Or you can double encode the values by coloring the pie numerically: the value of the slice drives the saturation of the color. 

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Sort your pie chart slices starting at 12 o'clock

Sorting

Sorting your slices in ascending or descending order and starting them at 12 o’clock might help the user to read the data. There is no real scientific proof for this but it is the natural way we read a clock and it also results in a calmer design.

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Labeling

You can apply a categorical label directly or via a legend. In general, direct labeling is preferred. That way your eyes don’t have to go back and forth between slice and legend. (Our tool offers a lot of direct label options to optimize the placement of the labels.) However, if your pie chart is colored categorically and the space around the pie is too small, using a legend is a perfect way to make the pie chart design calmer. Value labels are usually applied directly to the slices.

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Apply data point styling to a certain slice in your pie chart

Data point styling

You can emphasize a viewpoint or an analysis angle by applying data point styling to a certain slice. Differentiating the color, the label styling and the size of a slice attracts the attention of the viewer to the point you want to highlight. Attention: be aware that some data point styling options, like increasing the radius of a slice or pulling the slice out of the pie can distort the translation of the data.

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Create a rest category so you can still use a pie chart

Rest category

If your data contains a ton of categories, there is still a way you can use a pie chart. If the data allows it, and if it suits the message you are trying to convey, you can combine all small categories into one ‘other’ category and label it as such. This does not work for all datasets. Ideally, the ‘rest’ category is not bigger than the next to last category and the total number of categories is not much bigger than 5.

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Are you ready to make your own pie charts with Datylon? 

Create a Datylon account and get started online or download a 14-day trial version of Datylon for Illustrator. Connect with a Datylon expert for a free demo session. 

Pie chart inspiration

Scroll, and click on the images below to find inspiration samples of pie charts and part-to-whole visualizations. With your Datylon account, you can use these designs, customize them and update them with new data.