How to Combine Two Data Sets in Excel Graph

Putting two different sets of data into a single Excel chart is one of the best ways to spot relationships and compare performance at a glance. Instead of flipping between two separate graphs, you can see the whole story in one place. This tutorial will walk you through how to combine two data sets in an Excel graph, covering the two most common methods depending on what you're trying to show.

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Why Combine Data Sets in an Excel Graph?

Before diving into the "how," let's quickly cover the "why." Visualizing multiple data series on a single chart is incredibly powerful for a few key reasons:

• Comparison: The most obvious benefit is direct comparison. Plotting your sales from this year against your sales from last year on one line chart instantly shows you growth or decline.
• Correlation: It helps you spot potential relationships. For example, does your marketing spend (one data series) increase website traffic (a second data series)? Plotting them together makes it easier to see if they move in tandem.
• Context: Combining data provides valuable context. A chart showing just your website revenue is useful, but a chart showing both revenue and the number of sales transactions tells a much richer story about average order value.

First, Prepare Your Data For Graphing

A clean chart starts with clean data. Before you try to combine anything, take a moment to set up your spreadsheet correctly. Good data organization will prevent 99% of common Excel charting headaches.

Let's imagine you're a marketer at an e-commerce store. You want to see the relationship between your monthly Facebook Ads spend and the website sessions they generated for the first half of the year.

Your data should be organized in columns, with a shared label in the first column. This shared label (often a date or category) will become your horizontal X-axis.

Organize Data in Columns

Each set of data you want to plot should have its own column. The first column should contain the labels for your X-axis (e.g., months, quarters, product categories).

Here’s a good layout:

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Be Mindful of Different Scales

Notice a key detail in our example: "Facebook Ads Spend" is measured in thousands of dollars, while "Website Sessions" is in tens of thousands of visitors. These are on completely different scales. If you plot them on the same vertical Y-axis, the smaller number set (Ad Spend) will look like a flat line at the bottom, making the chart useless.

This is a common scenario, and Excel has the perfect solution: a secondary axis. We will cover this in detail in the first method below.

Method 1: Using a Combo Chart for Data with Different Scales or Types

The "Combo Chart" is Excel's purpose-built feature for plotting two data sets that you want to visualize differently or that have very different value ranges. It's perfect for our ad spend vs. traffic example, where we might want to see spend as columns and traffic as a line.

Step 1: Select Your Data

Click and drag to highlight the entire range of data you want to chart, including the column headers and the shared X-axis labels (in our case, the 'Month' column).

Step 2: Insert a Combo Chart

With your data selected, navigate to the Insert tab on the Excel ribbon. In the "Charts" section, find the small icon that looks like a column chart with a line on it and click on it. It’s the "Insert Combo Chart" button.

Select Create Custom Combo Chart... from the bottom of the dropdown menu. This gives you the most control.

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Step 3: Configure Your Chart and Secondary Axis

A new window called "Insert Chart" will pop up. This is where you tell Excel how to handle each of your data series.

• At the bottom, you'll see your two data series ("Facebook Ads Spend" and "Website Sessions").
• For each series, you can choose a Chart Type from the dropdown menu. Let's make "Facebook Ads Spend" a Clustered Column chart and "Website Sessions" a Line chart.
• Here comes the most important part! Look at the right side of the window for the Secondary Axis column. Since "Website Sessions" has much larger values, check the box in this column for that data series.

Once you check that box, you'll see the chart preview update immediately. Excel creates a second vertical axis on the right side of the chart just for the Website Sessions data. Now both data series are clearly visible because each has its own scale to work with.

Click OK, and your chart will be inserted into your worksheet.

Step 4: Tidy Up Your Chart

The chart looks good, but it's not finished. A professional chart is a well-labeled chart.

• Give it a title: Click on "Chart Title" and give it a descriptive name like "Ad Spend vs. Website Sessions."
• Label your axes: Click on the chart, then click the green "+" icon that appears on the right. Check the box for "Axis Titles." Excel adds placeholders. Label your left vertical axis "Ad Spend ($)" and your right vertical axis "Website Sessions" so everyone knows what each scale represents.

Method 2: Adding a Second Data Series to an Existing Chart

Sometimes you don’t have wildly different scales. You might just want to compare two very similar metrics, like sales for two different products over time. In this case, creating a combo chart might be overkill. A quicker method is to simply add a second data series to a chart you've already made.

Let's use a new example: comparing the monthly unit sales for "Product A" vs. "Product B."

Step 1: Create a Chart with the First Data Set

First, create a simple chart using just the first data series. Highlight the "Month" and "Product A Sales" columns, go to Insert > Charts, and select a 2-D Line chart.

You'll now have a simple line chart showing just the performance of Product A.

Step 2: Open the Select Data Source Window

Right-click anywhere in the empty space of your chart area and choose Select Data… from the context menu.

This opens the "Select Data Source" window. This is the control center for what data your chart displays.

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Step 3: Add a New Series

Everything you see on the left side under "Legend Entries (Series)" are the data sets currently being plotted. We only have "Product A Sales" for now.

Click the Add button.

Step 4: Define the New Series Data

A small "Edit Series" window will appear. It has two fields you need to fill in:

1. Series name: Click in this field, then click on the cell in your spreadsheet that contains the name for your second data set (the cell with the text "Product B Sales (Units)").
2. Series values: Delete anything that's currently in this field (it defaults to ={1}). Click into the field, then select the entire range of data values for Product B, from the first value to the last.

Click OK in the "Edit Series" window, then click OK again in the "Select Data Source" window. Your chart will instantly update to include a second line representing Product B's sales, complete with an updated legend so you can tell them apart.

Final Thoughts

As you can see, combining two sets of data in an Excel graph is straightforward once you know whether you need a combo chart for different data types or if you just need to add a second series of similar data. These techniques turn a flat spreadsheet into a powerful visual tool for comparing metrics and discovering important trends in your business performance.

While mastering these Excel skills is invaluable, the real bottleneck for marketers and business owners is often getting all that data into the spreadsheet in the first place—downloading reports from Google Analytics, Facebook Ads, and Shopify, then trying to stitch it all together. This is why we built Graphed to help. Instead of manually exporting CSVs and building charts, you can connect your data sources and just ask for the comparison you need in plain English, like "Compare my Facebook Ads Spend to Shopify revenue for the last 6 months." We automatically create real-time, shareable dashboards that do all the heavy lifting for you.