Combo and Dual Axis Tableau Charts present two different variables on the same graph.  For example, sales and profits.  These are different than one metric, like sales, with multiple dimensions or segments (i.e. Consumers, Enterprise, SMBs).  Dual Axis Tableau Charts compare two different metrics, which often have different scales.

If not presented correctly, they can lead to wrong data interpretation. However, when you have limited real estate and you want to quickly establish the relationship between 2 variables, the dual Y-axis Tableau chart can be useful.  Using a dual axis Tableau chart, you can easily validate/invalidate relations between two variables with different magnitudes and scales of measurement, as well as gauge a general idea of the trend.

How to Make Dual Axis Chart in Tableau

  1. Let’s plot the Order Quantity vs. the Product Base Margin (on Columns) by Product Subcategory (on Rows).
  2. This will create two panes with bar charts.
  3. Click the down arrow of the Product Base Margin pill and change it to an average. Then click it again and select Dual Axis in Tableau.
  4. This will now create a chart with a random assortment of dots.  This particular visualization doesn’t give us much insight.
Dual Axis Tableau Chart
  1. So, on the Marks card, click where it says Sum(Quantity) and change that mark to a bar clicking the down arrow next to Automatic.  When using Tableau dual axis or combo charts, you want to use two different mark types to avoid confusion.  
  2. Next, flip the Tableau axis at the top. This gets us much closer to insights, but we can do more.  
  3. Change the color of the bars to gray from the Tableau 10 Medium color palette.  Make the Product Base Margin a dark blue by selecting that color from the Color Blind 10 palette.  Note that Tableau allows you to mix and match color palettes or upload your own custom palette.
  4. Right click the right axis in Tableau and format the font to be dark blue.  Increase the font size as well.  This helps your users visually see which Tableau axis and marks are related.
  5. Now, click on the profit ratio pill, then click the sort descending icon on the top menu.
  6. Finally, right click one of the circles and then select Drop Lines>Show Drop Lines.  Now, if someone clicks one of the blue marks it will create a line to the Tableau axis and show its exact value.  This helps avoid any further confusion about which Tableau axis is which.
  7. We now have a chart that packs a lot of insight into a small amount of space.  For instance, we can see that Telephones and Communication are the most profitable for us, but we don’t sell that many, whereas we sell about the same amount of Binders and Accessories at much lower profit.  This type of insight can lead to real action.
Dual Axis in Tableau

We have shared Tableau tips on how to deal with huge data sets. Now, we’ve shown you what you can use when you have limited real estate to work with and extract insights. To learn more about the different Tableau features you can use depending on your needs, we offer an affordable online course as well as virtual courses for employees.