How to Make a Combo Chart in Google Sheets

Trying to show two completely different types of data on the same chart, like revenue in dollars and unit sales in numbers, can feel impossible in Google Sheets. You end up with one set of bars towering over the other, making any comparison meaningless. This is exactly what a combo chart is designed to fix. This article will walk you through exactly how to create and customize a dual-axis combo chart to clearly visualize the relationship between two different metrics.

What Is a Combo Chart (and Why Should You Use One)?

A combo chart, also known as a combination chart, is a single visualization that displays two or more data series using a combination of different chart types. The most common combination is a bar or column chart paired with a line chart. Its main superpower is its ability to use two different scales on a left and right vertical axis, which is sometimes called a dual-axis chart.

You should use a combo chart when you need to:

• Compare metrics with different scales. This is the classic use case. Imagine you're comparing monthly sales revenue (e.g., $50,000) with the conversion rate for that month (e.g., 2.5%). On a standard chart with one axis, the line for the conversion rate would look completely flat and useless next to the huge bars for revenue. A combo chart gives each metric its own axis, so both are displayed clearly.
• Show a relationship between two variables. Do more website sessions lead to a higher number of sign-ups? Does increasing your ad spend affect your click-through rate? A combo chart puts these two pieces of information side-by-side, making it easy to spot trends, correlations, or inverse relationships.
• Mix value types and percentages. A combo chart elegantly handles showing a raw number (like a budget of $10,000) alongside a percentage (like the percent of budget spent) in the same view without any visual confusion.

Preparing Your Data for a Combo Chart

Before you insert any chart, a well-organized data set is essential. Messy data leads to a messy chart. For a combo chart, your data in Google Sheets should be structured in a simple, clean table format.

Follow this layout for the best results:

• First Column (A): This should be your X-axis, or the shared category for all your data. This is typically a time period like Month, Date, or Quarter, but it could also be categories like Product Name, Campaign Name, or Sales Rep.
• Subsequent Columns (B, C, etc.): Each of these columns should represent a different data series you want to plot on the chart. These are your metrics, like "Revenue," "Units Sold," "Website Sessions," or "Conversion Rate."

Here is a simple example data set we'll use for the tutorial. It shows monthly ad spend versus new customer sign-ups.

Notice how 'Month' is the first column, and the two metrics we want to compare, 'Ad Spend' and 'Sign-ups', are in the following columns. Always include a clear header row for your columns - Google Sheets uses these to create the default labels for your chart.

Step-by-Step Guide: Creating Your First Combo Chart

Once your data is organized, creating a basic combo chart is quick. Let’s use the sample data from above to build one.

1. Select Your Data

Click and drag your mouse to highlight the entire range of data you want to include in the chart, including the header row. In our example, you would select cells A1 through C7.

2. Insert the Chart

With your data selected, go to the menu at the top of the screen and click Insert > Chart. Google Sheets will automatically analyze your data and create what it thinks is the best chart type. Often, it might default to a column chart or line chart, but sometimes it will recognize the need for a combo chart right away.

3. Choose the "Combo chart" Type

If Google Sheets didn't already select it, we need to change it. Your new chart will appear with the Chart editor sidebar open on the right. If it's not open, double-click on the chart itself.

In the editor sidebar, under the Setup tab, click the dropdown menu under 'Chart type'. Scroll down until you see the 'Combo chart' option and select it.

At this point, you'll have a combo chart, but it probably looks wrong. As you can see in our example, the "Ad Spend" columns are massive, while the "Sign-ups" show up as tiny columns at the bottom. This is because both series are being plotted against the same left-side axis, which can't properly accommodate both scales. This is the exact problem we need to fix with customization.

Customizing Your Combo Chart for Maximum Clarity

Creating the initial chart is easy, making it clear and useful is where the real work begins. The next steps will transform your messy chart into a powerful visual report.

1. Add a Secondary Axis (The Most Important Step)

The solution to our scale problem is to give one of our data series its own axis on the right side of the chart. This allows each metric to be displayed according to its own scale, making both easy to read.

• In the Chart editor, click on the Customize tab.
• Click on the Series dropdown section to open it.
• By default, the settings for your first series ('Ad Spend') will be shown. Click the 'Apply to all series' dropdown menu and select the other series - in our case, 'Sign-ups'.
• Under the formatting options for this series, you will see a dropdown labeled Axis. It will be set to 'Left axis'. Click it and change it to Right axis.

The moment you make this change, your chart will instantly make more sense. You now have two vertical axes: a left one for 'Ad Spend' and a new right one for 'Sign-ups'.

2. Change the Chart Type for an Individual Series

A true combo chart combines two different chart types. The most effective combination is typically columns for one metric and a line for the other. This visual distinction helps the brain process the two datasets separately but simultaneously.

• While still in the Customize > Series section, make sure you still have the 'Sign-ups' series selected.
• Change the Type from 'Columns' to Line. You can play around with the line thickness, point shape, and other visual styles here as well to make it stand out.

Your chart now clearly displays Ad Spend as columns against the left axis and Sign-ups as a trending line against the right axis. Now we can easily see how sign-ups trended as ad spend changed month-over-month.

3. Final Touches: Good Titles and Labels

A chart without labels is just artwork, it's practically useless for reporting. Make sure anyone who sees it can understand it without you there to explain it.

• Navigate to the Chart & axis titles section in the Customize tab.
• Chart title: Give your chart a descriptive title, like "Monthly Ad Spend vs. New Customer Sign-ups."
• Left vertical axis title: Label your left axis accurately. In this case, "Ad Spend ($)."
• Right vertical axis title: Crucially, don't forget to label your new right axis! Label it "Number of Sign-ups."

Adding clear axis titles removes any guesswork for your audience, ensuring they know exactly what each set of bars and lines represents.

Practical Examples and Use Cases

Now that you know how to build a combo chart, here are a few other common business scenarios where they deliver powerful insights.

Marketing: Advertising Spend vs. Return On Ad Spend (ROAS)

You can plot your advertising spend in dollars against your ROAS, which is a multiplier (e.g., 3.5x). Did spending more on your Google Ads campaign last month actually improve its efficiency, or did it lead to diminishing returns?

• Left Axis (Columns): Ad Spend ($)
• Right Axis (Line): ROAS

E-commerce: Website Traffic vs. Conversion Rate

Your Shopify store had a huge spike in traffic last weekend from a social media post, but did those new visitors actually buy anything? A combo chart can tell the story.

• Left Axis (Columns): Website Sessions
• Right Axis (Line): E-commerce Conversion Rate (%)

Sales: Target Quota vs. Actual Revenue Booked

Visualize your team's sales target against their actual performance throughout the year. The contrast between a target line and performance bars is a classic and highly effective use of a combo chart.

• Left Axis (Columns): Actual Revenue ($)
• Right Axis (Line): Monthly Sales Quota ($)

Final Thoughts

Combo charts are an essential tool for clearly displaying two different datasets in a single, coherent visualization within Google Sheets. By mastering the use of a secondary axis, you can turn a confusing jumble of bars into a clear report that reveals important relationships between your key business metrics.

Of course, building powerful reports often involves pulling data from multiple places and hours of manual configuration tinkering with chart settings. At Graphed, we automate all of this tedious work. Instead of building charts manually, you can simply connect your data sources (like Google Analytics, Shopify, and your ad platforms) and ask for what you need in plain English. You can even ask for the charts from this article by saying "show me a combo chart comparing ad spend to sign-ups," and get back a real-time, interactive dashboard in seconds.