How to Superimpose Graphs in Excel

Trying to show two different types of data, like sales revenue and units sold, on a single Excel chart can be tricky. You’re not alone if you’ve ever tried to plot them together and ended up with a jumbled, unreadable mess. The solution is to superimpose, or layer, one graph on top of another. This article will show you exactly how to do it step-by-step, transforming your confusing data into a clear, insightful visual.

What Does "Superimposing Graphs" Mean in Excel?

When you "superimpose" graphs in Excel, you're essentially combining two or more charts into one cohesive visual. This allows you to tell a more complete story with your data by comparing different metrics on the same timeline or against the same categories.

There are two key ways to think about this:

• The Combination Chart: This is the most common and powerful method. You merge two chart types, like a column chart and a line chart, into a single graph. It’s perfect for comparing values with different scales, such as website traffic (in the thousands) and conversion rates (as a percentage).
• The Manual Overlay: This involves making two separate charts transparent and physically placing one on top of the other. It’s a bit of a manual hack for specific visual effects but isn't as dynamic or practical for most business reporting needs.

For most situations, the Combination Chart is what you need. Let’s focus on building a professional Combo Chart to compare metrics that seem impossible to visualize together.

How to Superimpose Graphs with a Combo Chart and Secondary Axis

The best way to show two vastly different data sets on one graph is by using a combination chart with a secondary axis. The secondary axis allows you to plot data with a completely different scale, so one metric doesn't dwarf the other.

Let's walk through a classic marketing scenario: you want to visualize your monthly website sessions alongside the number of new marketing-qualified leads (MQLs) generated each month. Sessions will be in the tens of thousands, while MQLs will be in the hundreds. Here’s how to build the perfect chart for this.

Step 1: Set Up and Organize Your Data

First, make sure your data is organized in a clean table. Your first column should contain your labels (in this case, the months), and the subsequent columns should contain the data series you want to plot.

Your spreadsheet should look something like this:

Step 2: Create a Basic Chart

Highlight your entire data table, including the headers. Go to the Insert tab on the Excel ribbon and find the Charts section. A simple 2-D Clustered Column chart is a good starting point.

When you insert it, you'll immediately see the problem. The bars for MQLs are barely visible because their values (hundreds) are tiny compared to the Sessions values (thousands). The orange MQL bars look like a blurry line along the bottom.

This is where superimposing with a secondary axis comes in handy.

Step 3: Change to a Combo Chart Type

Right-click on your chart area and select Change Chart Type… from the context menu.

In the "Change Chart Type" window, navigate to the Combo category at the bottom of the list on the left. This is Excel’s dedicated tool for layering different graph types.

Step 4: Configure Your Chart Types and Secondary Axis

Now you get to configure how your data series will be visualized. In the bottom half of the window, you'll see your two data series ("Sessions" and "MQLs") with dropdown menus for their chart type.

1. For the Sessions series, keep the chart type as Clustered Column.
2. For the MQLs series, change the chart type to Line With Markers. This will help a trend stand out against the volume indicated by the columns.
3. Here's the most important part: to the right of the "MQLs" series, check the box for Secondary Axis.

As soon as you check that box, you'll see the chart preview at the top come to life. A new vertical axis appears on the right for the MQL values, and your MQL line is now perfectly visible against the session columns. Click OK.

Step 5: Format and Style Your Chart for Clarity

Your combo chart is technically finished, but a little formatting goes a long way. To make it professional and easy to read, you should:

• Add a Chart Title: Give it a descriptive title like "Monthly Website Sessions vs. MQLs." You can do this by clicking the default "Chart Title" text at the top.
• Label the Axes: You have two vertical axes, and they need labels! Click on the chart, then click the small green "+" icon that appears on the right. Check the box for Axis Titles. Then, edit the new text boxes to label the left axis "Website Sessions" and the right axis "Number of MQLs."
• Adjust Colors: You can right-click on any data series (the bars or the line) and select "Format Data Series…" to change the colors of the fill and border to match your brand or presentation.

After a few quick styling adjustments, you have a clear, professional, superimposed chart that tells a much better story about your marketing performance.

The Manual Way: Overlaying Transparent Charts

While the Combo Chart method is best for most analytical needs, there might be rare occasions where you want to physically overlay two charts. For example, you might want to overlay two histograms to compare distributions.

Be warned: this method is manual, hard to align perfectly, and doesn't update as gracefully as a Combo Chart. But here’s how to do it if you are feeling adventurous.

Steps for Manual Overlaying:

1. Create Two Separate Charts: Create two individual charts from two separate data tables. For example, two different line graphs.
2. Make The Chart Areas Transparent: Click on the first chart to select it. In the right sidebar, find the "Format Chart Area" option. Under "Fill," choose No Fill. Under "Border," choose No Line.
3. Make the Plot Areas Transparent: Now click inside the gridlines to select the Plot Area. In the "Format Plot Area" sidebar, also set the Fill to No Fill.
4. Repeat for the Second Chart: Apply these same transparent settings to your second chart.
5. Align and Manually Superimpose: Now you can click and drag one chart directly on top of the other. Carefully resize and align the axes so they match up perfectly. You can use the Alt key while dragging to snap the chart to the cell grid in Excel, which can help with alignment.

This trick gives you a layered look but is mostly for static visual effect rather than an interactive or dynamic report. For everyday data analysis, always default to the Combo Chart method.

Final Thoughts

Superimposing graphs in Excel is an invaluable skill for anyone wanting to create more insightful reports. By using a Combination Chart with a secondary axis, you can easily compare two different data sets with different scales, turning confusing tables into clear visuals that tell a complete story. It's the best way to show the relationship between metrics like ad spend and revenue, or traffic and conversions.

Once you get comfortable creating these charts, you might realize how much time goes into manually preparing data and repeating these steps for weekly or monthly reports. This is where modern analytics tools can change the game. We built Graphed to eliminate this manual work entirely. You can connect all your data sources like Google Analytics, Shopify, and your ad platforms in a few clicks, then create complete, real-time dashboards just by describing what you want to see. Instead of fiddling with secondary axes, you can simply ask, "Compare my monthly sessions from Google Analytics to my MQLs from HubSpot," and an interactive dashboard gets built for you in seconds.