Combined Axis vs Dual Axis Charts in Tableau

Overview

A dual-axis chart is a type of data visualization that allows you to plot two sets of data on a single chart, using two separate vertical axes (y-axes). This chart is especially useful when you want to compare two variables that have different scales or units.

A combined axis chart on the other hand is a type of visualization where multiple datasets share the same axis—usually the same vertical (y-axis) or horizontal (x-axis)—to provide a clear comparison. Unlike a dual-axis chart, which has separate axes for different datasets, a combined axis chart uses one shared axis for all datasets.

How to create a dual axis chart?

Using the sample – superstore dataset, you can create a dual axis chart comparing Sales and Profit for different months as follows.

• Drag Order Date to the columns shelf and set the level of detail to month.

• Drag SUM(Sales) and SUM(Profit) to the rows shelf.

• Open the drop-down menu on one of the measures and select Dual Axis as shown below.

Note, executing this generates a dual axis chart comparing sales and profit by month. Notice, the view has two separate axes representing the two variables being compared.

How to create a combined axis chart?

Using the same variables, you can create a combined axis chart as follows.

• Drag Order Date to the columns shelf and set the level of detail to month.

• Drag SUM(Sales) to the rows shelf as shown below.

Drag the second variable (in this case Profit) onto the axis of the current view.

Notice, when you do so the axis is highlighted as shown below.

Dropping the field on the axis creates a combined axis chart as shown below.

Notice that the view has a single axis – giving you a clear comparison between the two variables.

Conclusion

In summary, both dual-axis and combined-axis charts are effective visualization tools, but they serve different purposes:

• Dual-axis charts utilize two separate vertical axes (y-axes) to plot datasets with different scales or units, making them ideal for comparing variables that don't share a common range (e.g., revenue vs. customer count).

• Combined-axis charts, on the other hand, share the same axis for all datasets, simplifying the visualization and providing a clear comparison when the data uses the same units or similar scales (e.g., profit vs. sales in dollars).

The choice between these depends on your data's nature and the clarity you aim to achieve in your presentation.

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