How to Make a Graph with Two Y Axis in Excel

Trying to show two completely different types of data on a single Excel graph can be frustrating. If you plot your website traffic (in the thousands) and your conversion rate (a small percentage) on the same axis, the conversion rate line will look like a flat line squashed at the bottom. This tutorial will walk you through creating a dual y-axis graph in Excel, an effective and professional way to visualize data with different scales and tell a clearer story.

Why Use a Dual Y-Axis Graph?

A dual y-axis graph, also known as a combination chart, is your best option when you need to compare two data series that are measured on wildly different scales. While the two datasets share a common x-axis (usually a measure of time, like days or months), they each have their own vertical y-axis scaled appropriately for their values.

This is perfect for visualizing cause-and-effect relationships or correlations between two different metrics. Common examples include:

• Marketing Campaigns: Comparing monthly Ad Spend (in thousands of dollars) to Click-Through Rate (a small percentage).
• Sales Performance: Charting Total Revenue (large numbers) against the Number of Deals Won (smaller numbers).
• Website Analytics: Showing the relationship between Total Sessions (large numbers) and Conversion Rate (a small percentage).

By putting these on a single graph, you can instantly see trends and relationships. For example, you might see that as ad spend increases, your click-through rate starts to decline, providing a valuable insight for your campaign strategy.

Step 1: Preparing Your Data in Excel

Before you build your graph, your data needs to be organized properly. Failing to set up your data logically is where most issues begin. The best structure is a simple table with your shared dimension in the first column and your two different metrics in the columns next to it.

For your x-axis, which is the data plotted horizontally, you should use a sequential data set like dates, months, or years. The two subsequent columns will be your y-axis data.

Here’s a simple data layout for tracking sales revenue versus units sold:

Notice how "Revenue" is a large number and "Units Sold" is a much smaller one. These are perfect candidates for a dual y-axis graph.

Step 2: Creating the Graph with Two Y-Axes

With your data cleanly organized, you're ready to create the chart. This process involves creating a "Combo" chart and then specifying that one of your data series should use a secondary axis.

Making a Combo Chart

First, highlight the entire data set you want to visualize, including the column headers.

1. Navigate to the Insert tab on the Excel ribbon.
2. In the Charts section, click on Recommended Charts.
3. A dialog box will pop up. Instead of choosing a recommended chart from the first tab, click on the All Charts tab at the top.
4. Scroll down and select Combo from the menu on the left. This is Excel's dedicated section for mixing chart types and creating a secondary axis.

Assigning the Secondary Axis

You’ll now see a preview of your chart along with options for each data series. This is where you bring your second y-axis to life.

1. By default, Excel will likely try to represent both data series as a Clustered Column. You can leave one as is ("Revenue") but it often improves readability to change the other to a line chart ("Units Sold"). In the dropdown next to "Units Sold," select Line.
2. Now for the most important step: locate your second data series ("Units Sold") in the list. To the right of it, you'll see a checkbox labeled Secondary Axis. Go ahead and check that box.

As soon as you check the box, the chart preview will update. You'll see the "Revenue" columns plotted against a primary axis on the left and the "Units Sold" line graphed against a new, secondary axis on the right. Each axis will have its own scale that fits its data, making both perfectly visible.

Click OK, and the graph will be added to your spreadsheet.

Step 3: Polishing Your Dual Y-Axis Graph

Your graph is functional now, but it’s not yet clear or professional. A few simple tweaks will make it much easier for anyone to understand at a glance.

Give Your Axes Clear and Descriptive Titles

A dual-axis chart without labeled axes is confusing. To add them:

1. Click on your chart to select it.
2. A small plus sign (+) will appear on the top right. Click it to open the Chart Elements menu.
3. Check the box for Axis Titles.
4. You’ll now have text boxes on your primary and secondary y-axes. Click into each one and give it a clear, descriptive title. For example: "Total Monthly Revenue ($)" for the left axis and "Total Units Sold" for the right axis. This immediately tells the viewer which data to read against which scale.

Use Color to Connect Data to an Axis

Another powerful way to improve readability is to use color to visually connect a data series to its corresponding axis. If your revenue bars are blue, make the primary y-axis title and labels blue. If your unit sales line is orange, make the secondary y-axis title and labels orange.

To do this:

1. Right-click on the axis title or the axis numbers you want to change.
2. From the pop-up menu, select Format Axis... or Format Axis Title....
3. In the formatting pane that appears on the right, look for the text options (usually under an icon that looks like a text box or under the paint bucket 'Fill & Line' tab).
4. Find the Color option and select the same color as the corresponding data series on your chart.

This subtle design choice makes it instantly intuitive which line corresponds to which axis, eliminating any potential confusion.

Provide a Clear, Descriptive Chart Title

Finally, give your chart a title that explains exactly what it's showing. Something like "Monthly Revenue vs. Units Sold" is concise and informative. An unclear title forces your audience to spend unnecessary time trying to figure out what they're looking at.

Common Mistakes to Avoid

Dual-axis graphs are powerful, but they can be misleading if used improperly. Keep these pitfalls in mind:

• Comparing Unrelated Data: A dual y-axis visually implies a relationship between two metrics. Don't use it to compare things that have no logical connection, like "Employee Happiness Score vs. Total Company Revenue." It can create a false impression of correlation.
• Manipulating the Axes: You can make data look drastically different by changing the minimum and maximum values of your y-axes. This can exaggerate or minimize a trend. For the sake of honesty and clarity, it's generally best to start your axes at zero unless there's a very compelling reason not to.
• Over-Complication: While you can technically add more than two data series, it's not a good idea. A dual y-axis chart with three or four series becomes a chaotic mess of overlapping lines and columns that’s almost impossible to read. Stick to two distinct metrics for maximum clarity.

Final Thoughts

Creating a dual y-axis graph in Excel is a fantastic skill for cleanly presenting complex data, helping you uncover and communicate relationships between different metrics on a single, easy-to-read chart. By learning how to set up your combo chart and polish its design, you can build dashboards that tell a much more compelling data story.

While Excel is great for these one-off analyses, the process can become tedious when you have to do it every week across a dozen data sources. The manual work of exporting CSVs, cleaning spreadsheets, and rebuilding the same reports is why we built Graphed. We wanted to make getting insights as simple as having a conversation. Graphed connects directly to platforms like Google Analytics, Shopify, and your CRM, and lets you build real-time, interactive dashboards just by describing what you want in plain English, turning hours of chart-building into seconds.