How to Create an Excel Chart with 2 Y Axes

Trying to compare revenue in dollars against units sold on the same Excel chart can feel impossible. One set of numbers is in the thousands, while the other might be in the dozens, making your unit sales look like a flat line at the bottom of the graph. This is a common problem when your data series have wildly different scales or units, and the solution is a chart with two Y-axes. This tutorial will show you exactly how to build one, step by step.

Why Use a Chart with Two Y-Axes?

A dual-axis chart, sometimes called a combination or combo chart, is a single graph that uses two different Y-axes (the vertical axes) to plot two different types of data. This allows you to visualize the relationship between two data series that would otherwise be difficult to compare because of their different magnitudes or units of measurement.

Imagine you run an online store. You track both your monthly revenue (dollar amounts) and the number of ads you've run (a simple count). Let's say your data looks like this:

• January Revenue: $50,000, Ads Run: 15
• February Revenue: $55,000, Ads Run: 20
• March Revenue: $62,000, Ads Run: 25

If you plot this on a standard chart with one Y-axis that goes from $0 to $70,000, your ad counts (15, 20, 25) will be squished at the very bottom, practically invisible. You can't see the trend or pattern in your ad campaign efforts.

By adding a secondary Y-axis on the right side of the chart specifically for the "Ads Run" data, you give each series its own scale. The left axis can scale for dollars, and the right axis can scale for the count of ads. Suddenly, you can see both trends clearly and explore their relationship. Did running more ads lead to more revenue?

Common Scenarios for Dual-Axis Charts

This technique is incredibly versatile and applies to almost any industry:

• Sales Reporting: Comparing total revenue ($) to the number of units sold or deals closed.
• Marketing Analytics: Visualizing ad spend ($) against website traffic (sessions) or conversion rate (%).
• Financial Analysis: Plotting a company's stock price ($) and its trading volume (number of shares).
• Project Management: Showing project budget spent (%) against tasks completed by count.
• Manufacturing/Operations: Tracking production output (units) versus machine uptime (%).

Step-by-Step: Creating an Excel Chart with 2 Y-Axes

Creating a dual-axis chart is surprisingly easy with Excel's built-in Combo chart type. Let's walk through the process using a classic sales example: tracking Monthly Revenue and Units Sold.

Step 1: Set Up Your Data

First, organize your data in a clean, tabular format. Your first column should contain your X-axis labels (like months, days, or quarters), and the subsequent columns should contain the data series you want to plot.

For our example, the data looks like this in Excel:

Step 2: Insert a Combo Chart

Once your data is ready, select the entire data range, including the headers (in our example, a selection from A1 to C7).

1. Go to the Insert tab on the Excel ribbon.
2. In the Charts section, click on the small icon that looks like a combination of a column and line chart. This is the Insert Combo Chart icon.
3. From the dropdown, select Create Custom Combo Chart... This gives you the most control.

Step 3: Assign a Secondary Axis

You'll now see the "Insert Chart" dialog box, focused on the Combo chart options. This is where the magic happens. You'll see each of your data series ("Revenue" and "Units Sold") listed. For each series, you can choose a chart type and decide whether to plot it on the secondary axis.

1. Choose Chart Types: It's a common practice to use different chart types to distinguish the two series. Let's leave "Revenue" as a Clustered Column and change "Units Sold" to a Line chart. This creates a really clear visual separation.
2. Enable the Secondary Axis: For the data series with the different scale ("Units Sold" in our case), check the box under the Secondary Axis column.

As you make these changes, Excel provides a live preview of what your chart will look like.

Click OK. Your dual-axis chart will now appear on your worksheet!

Step 4: Format and Refine Your Chart

Your chart is functional, but it's not finished. A great chart is one that is instantly understandable. Here are some critical formatting steps to make your work shine.

Add Descriptive Axis Titles

This is the most important step. Without clear titles, your audience won't know which axis corresponds to which data.

1. Click anywhere on your chart to select it.
2. Click the green "+" button (Chart Elements) that appears on the top-right corner.
3. Check the box for Axis Titles.
4. Excel will add placeholder titles. Click on each one to edit them. Your primary vertical axis (left) should be "Revenue ($)", and your secondary vertical axis (right) should be "Units Sold".

Other Formatting Tips:

• Give it a Clear Title: Change the chart title from the default "Chart Title" to something descriptive, like "Monthly Revenue vs. Units Sold".
• Adjust Colors: If you don't like the default colors, you can right-click on any data series (the columns or the line) and select "Format Data Series". Use the paint bucket icon to choose colors that offer good contrast.
• Add Data Labels: Using the Chart Elements ("+") menu, you can add Data Labels to show the exact values directly on the chart, which can be useful if precise figures are important.
• Check Your Legend: Excel automatically adds a legend. Make sure it's located in a place (like the top or bottom) that doesn't interfere with the chart data.

Best Practices for Creating Dual-Axis Charts

A dual-axis chart is a powerful tool, but it can also be misleading if not used carefully. Follow these principles to keep your charts honest and clear.

• Label Everything: We can't say it enough. Obvious axis titles, a descriptive chart title, and a clear legend are non-negotiable.
• Pick Your Chart Types Wisely: The column-and-line combination is popular for a reason - it's easy to read. Avoid plotting two sets of columns or two sets of bars, as they can overlap and create a visual jumble.
• Don't Add a Third Series: A dual-axis chart is designed for comparing two data series. Adding a third variable makes the chart incredibly cluttered and defeats the purpose of providing clear insight.
• Beware of Misleading Correlations: One of the biggest pitfalls is manipulating axis scales to imply a stronger relationship between two series than actually exists. Because you have independent control over both Y-axes, you can stretch or shrink the scales to make lines overlap perfectly, suggesting a strong correlation that might be a coincidence. Always start your axes at zero (if it makes sense for your data) and be critical of the narrative your chart is telling. Just because two trends move together doesn't mean one causes the other.

Final Thoughts

Creating an Excel chart with two Y-axes is a simple and effective technique for comparing two different datasets on a single visualization. By using the Combo Chart feature and carefully labeling your axes, you can show the meaningful relationship between variables that have completely different scales, turning confusing data into a clear story.

Manually creating reports like these is a huge step up from raw spreadsheets, but it can still be a time-consuming weekly task. To get that time back, we built Graphed to automate the entire reporting process. You can connect all your data sources (like Shopify, Google Analytics, Salesforce, or even Google Sheets) and simply ask for what you need in plain English - like "create a chart comparing revenue to units sold for the last six months." Graphed instantly builds a live, professional dashboard for you, keeping everything up-to-date automatically so you can focus on insights, not manual report building.