Let’s talk about donuts! (Not the powdered sugar kind, sadly). Donut charts are an alternative to pie charts that offer a few extra advantages. In this post, I’ll talk about when (and when not) to use donut charts, and demonstrate how to make them in Tableau.
Why Use Donut Charts?
Donut charts share a lot of the same pros that pie charts do, and are useful in a lot of the same situations. Here’s some of the benefits of a donut:
- Familiar to most users (and frequently requested)
- Helpful for showing proportions that sum to 100%
- Works well when there are only a few categories
- Visual appeal of circles draws viewers in
They also have a few extra advantages that pie charts don’t:
- Space for extra information in the center, which replaces the hard-to-interpret center of a pie chart
- Cleaner look than pie charts, especially when there are more categories
- Better visual appeal (at least in my opinion! This one is a matter of taste, though)
Stakeholders often request pie charts, and donut charts can be a good way to satisfy that request while still appealing to aesthetics and good design – you can call out more information and make the chart more useful.
I use donut charts frequently for showing demographic data – here’s an example of using donut charts to show demographic data on my K12: Engagement Survey dashboard.
When NOT to Use Donuts
Unfortunately, donut charts share a lot of the downsides of pie charts. They can often be a good choice, but there are some situations where donuts really just don’t make sense, and are bad analytic practice. Don’t use a donut chart (or a pie chart!) in the following situations:
- When there are more than 10-ish categories, and you want the user to be able to see all of them. Donuts have a limit to how much information they can usefully show before the segments just get too small. (Note: Sometimes all you want to show is that there’s a lot of other, smaller categories involved, but don’t need users to actually know what those categories are – in this situation, a donut can still make sense.)
- When the segments are similar in size, but you still want to highlight the differences. Humans are bad at comparing angles, and if you have a bunch of similar-sized segments, it’s difficult for your users to tell which is the largest. Use a bar chart or other visual instead.
- When you have lots of specifics you want to call out. If you need to highlight more than 4 or 5 key points on your chart, a donut probably just doesn’t have enough room.
How To Make a Donut Chart in Tableau
Donut charts aren’t a native chart type in Tableau, but they’re not too complicated to make. The key is using a “dummy axis” of 0 to overlap two pie charts.
(Note: There’s also a method to create donut charts using polygons, which has some benefits! However, it’s significantly more complicated, so I’m going to leave it for a later post.)
Create a Dummy Axis
To start out, we’ll need a calculated field with a value of 0. I suggest keeping this simple – name the field “Zero”, and just put 0 in the field.
Once you’ve created your calculated field, drag two copies of it onto the columns card. Click the second pill and select “dual axis”.
Edit the Marks Cards
You’ll notice that creating this setup made three cards in the marks area. The first, “All”, affects every field – we’re going to leave that one alone. Let’s start by editing the third card, SUM(Zero)(2), which affects the top layer of the donut chart. We’re going to use this to make the hole in the middle of the donut.
Click on “Color”, and set the color to white. Then click on “Size” and drag the size down until you see a donut appear.
Don’t worry about the exact sizes right now – we’ll tweak those later. Just make sure you can see an o-shape.
Now let’s move back to the second card, SUM(Zero). We’re going to make this into a pie chart, where center is hidden by the white circle we made in the previous step.
Set the mark type to “pie”. Drag your categories field to the “colors” card, and whichever field you want to use to set the segment size to the “size” card.
Clean Up and Format
Now we have the fundamentals of our donut chart, and we just need to do some cleanup. Right click on the chart and select “format”. Head the “lines” icon on the far right of the format panel, and set “Zero Lines” to none.
Click on “Columns” and set the “Grid Lines” to none there as well.
Then head over to the borders icon, switch back to the sheets tab, and set the row dividers and column dividers to none.
Finally, head back to your chart, right click on the bottom axis, and uncheck “show header”.
You should now have a cleaned-up donut chart! From here, you can format this like you would any chart – change the colors, tweak the sizes, and add it to a dashboard.
I hope you found this tutorial helpful. Make sure to check out the suggested posts below before you go, and subscribe to get new posts as they come out!