How to Add a Secondary Axis in Excel

Visualize even more data

What to Know

  • Select the line (or chart) associated with the second data series. In the Chart Tools tab, select Format.
  • Choose Format Selection at the left of the screen. Select Secondary Axis in the right panel.
  • Customize the second axis by changing the text alignment or direction or the number format. The secondary axis appears on the right side.

This article explains how to add a secondary axis to a chart in Excel so you can view unlike things on the same graph. These instructions work in Excel in Microsoft 365, Excel 2019, Excel 2016, and Excel 2013.

How to Add a Secondary Axis in Excel

Excel's charts give you a variety of ways to visualize your data. For charts that utilize an X-and-Y-axis layout, you have the ability to view a series of data, which allows you to compare two different things, but those things usually have the same unit of measure. A secondary axis is used to compare two things that don't have the same unit of measure.

  1. First, select the line (or column) associated with the second data series.

    Click on the Line Representing a Data Series to Select It
  2. By selecting an element on a chart, the Chart Tools tab will appear in the ribbon.

    The Chart Tools Tab Only Appears in the Ribbon When a Chart Element is Selected
  3. Select the Format tab.

    The Format tab.
  4. To the far left, the Current Selection box should already display the series you selected. In this example, it's Series "Employees."

    The Current Selection Tools at Left Allow You to Format a Specific Data Series
  5. Select Format Selection.

    Select Format Selection.
  6. Now, in the right-hand panel, under Series Options, select Secondary Axis.

    Now Turn Your Attention to the Left-Hand Panel's Option to Add a Second Axis
  7. Once added, this second axis can be customized just like the primary axis. You can change the text alignment or direction, give it a unique axis label, or modify the number format.

  8. Now look at your chart. The secondary axis will appear on the right side, and Excel will even take some default guesses regarding scale. Compared to the first version of this chart, adding a second axis makes it much easier to compare the trends.

    With a Secondary Axis, the Graph's Trends Are a Lot More Accurate

When You Should Use a Secondary Axis in Excel

Consider this example showing a company's revenue versus its expenses for the last five years.

A Simple Excel Report Consisting of Yearly Values in Three Categories

Both of these are measured in dollars, so we can set up a line graph showing both of these in the same view to determine the relationship.

Revenue and Expenses Are Both Measured in Dollars

As you can see, the y-axis on the left is displaying the USD units, but what if you want to see if there's a similar trend as it pertains to costs and employees? The unit for Employees is people, not dollars, so you can't very well use the existing y-axis. This is where you should add a second axis to ensure your reader can accurately understand what the numbers mean.

When the Magnitude of Series is Different, Trends Can Become Skewed

A second reason is when the two series don't have data in the same magnitude. Consider, for example, the revenue of the company versus the employees. The chart above shows that when visualized together it doesn't provide much insight, because the number of employees is so low you can't determine what's happening with it.

Instead, you can add a second axis that has both its own units as well as its own scale, allowing you to really compare the two.

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