How to Make a Combo Chart in Google Sheets with AI
Creating a combo chart is the perfect way to display two different types of data on a single graph, like showing sales revenue in dollars alongside the number of units sold. This guide will walk you through creating a compelling combo chart manually in Google Sheets and then show you how built-in AI features can start to speed up the process.
What Exactly is a Combo Chart?
A combo chart, or combination chart, is exactly what it sounds like: a single chart that combines two different chart types. The most common combination is a bar chart and a line chart. This is incredibly useful when you want to show a relationship between two metrics that are on different scales.
For example, imagine you want to visualize your monthly sales revenue (measured in thousands of dollars) and your website conversion rate (a percentage). If you plotted them both as bars on the same axis, the conversion rate bars would be so tiny you couldn't even see them compared to the revenue bars. A combo chart solves this by giving each metric its own axis and its own visual style.
Primary Metric: Often shown as columns or bars, measured against the left vertical axis (Y-axis). [Example: Monthly Sales Revenue]
Secondary Metric: Often shown as a line, measured against the right vertical axis (Y-axis). [Example: Conversion Rate %]
This dual-axis approach lets you uncover insights that would be hidden if you looked at the data in separate charts or a messy table.
Why Should You Use a Combo Chart?
So, when is it a good idea to reach for a combo chart? They excel at a few specific jobs that regular charts can’t handle on their own.
1. Comparing Metrics with Different Units or Scales
This is the classic use case. You can easily plot metrics that are completely different from one another. For example, an e-commerce store might want to compare ad spend ($) with click-through rate (%). Or a SaaS company might visualize monthly recurring revenue ($) against the number of new subscribers (a count).
2. Highlighting the Relationship Between Two Metrics
Combo charts make it easy to see if two metrics move together. Do sales go up when you run more marketing promotions? Does customer satisfaction (measured on a 1-5 scale) drop when support ticket volume (a raw number) spikes? Laying a line chart over a column chart instantly exposes these kinds of correlations, helping you answer questions like, "What effect does X have on Y?"
3. Saving Dashboard Space and Providing Context
Instead of creating two separate charts that your team has to mentally connect, you can combine them into one powerful visual. This not only cleans up your report or dashboard but also makes the overall story easier to understand at a glance. Seeing the trends together in one place provides immediate context.
Step 1: Prepare Your Data in Google Sheets
Before you build any chart, your data needs to be structured properly. Clean data is the foundation of a great visualization. For a combo chart in Google Sheets, you’ll typically need at least three columns:
Column A: The dimension for your X-axis (the horizontal axis). This is usually a time period, like Month, Day, or Quarter.
Column B: The data for your first metric (your primary Y-axis). This will be plotted as columns. Let’s say this is "Revenue".
Column C: The data for your second metric (your secondary Y-axis). This will be plotted as a line. Let’s call this "Units Sold".
Here’s what a perfect dataset looks like:
Month | Revenue | Units SoldJan | $45,000 | 210Feb | $48,000 | 225Mar | $62,000 | 290Apr | $55,000 | 250May | $71,000 | 330
Make sure your headers are clear and that your numbers are formatted correctly (i.e., currency as dollars, units as numbers, etc.). Messy data leads to a confusing chart.
Step 2: How to Make a Combo Chart in Google Sheets (The Manual Way)
Once your data is ready, you can create the chart in just a few steps. Don't worry, it's easier than it looks!
1. Select Your Data Range
Click and drag your mouse to highlight all the data you prepared, including the headers. In our example, you'd select the range A1:C6.
2. Insert the Chart
With the data selected, go to the Google Sheets menu at the top of the screen and click Insert > Chart. Google will automatically analyze your data and insert a chart it thinks is best. Sometimes it guesses correctly, but often you'll need to adjust it.
3. Choose "Combo Chart" from the Chart Editor
A "Chart editor" sidebar will pop up on the right side of your screen. Under the Setup tab, click the dropdown menu under "Chart type" and scroll all the way down. You'll find the Combo chart option near the bottom. Click it.
Your chart will now change to show both series, likely with bars for both, which isn't quite right yet. We're getting close.
4. Customize Your Chart Series and Axes
This is the most important step. Here, we'll assign one of our metrics to a secondary axis and change its appearance to a line.
In the Chart editor, click on the Customize tab.
Click on the Series dropdown menu.
By default, the settings will apply to "All series". Change this dropdown to the metric you want to turn into a line - in our case, "Units Sold".
Now, look at the options below. You’ll see a dropdown menu labeled "Axis". Change it from "Left axis" to "Right axis". This creates a second scale for that metric.
Finally, you'll see a "Type" dropdown just above the Axis setting. Change it from "Columns" to "Line".
That's it! You should now have a proper combo chart with Revenue bars measured on the left axis and a Units Sold line measured on the right axis.
5. Add Finishing Touches
A good chart is easy to read. Use the Customize tab to improve your chart's clarity:
Chart & axis titles: Give your chart a descriptive title like "Monthly Revenue vs. Units Sold". Make sure both your left and right vertical axes are clearly labeled.
Colors: Choose distinct, contrasting colors for your bars and line so they're easy to tell apart.
Gridlines & Ticks: Adjust the gridlines to make the data points easier to read without cluttering the view.
Using AI to Create Your Chart in Google Sheets
Manually creating charts is a great skill to have, but it can be repetitive. Google Sheets has a built-in AI tool called Explore that can speed things up, especially for simple requests.
The "Explore" Feature
You can find the Explore icon at the bottom-right corner of your Sheet - it looks like a small square with a star in it. When you have your data selected, click it. A new panel will open up with insights and suggested charts. Explore uses natural language processing, meaning you can type questions in plain English.
How to Use It:
Select your prepared data.
Click the Explore button.
In the "Answers" section, you might see that Google Sheets has already suggested a combo chart for you! If it has, you can just click and drag it into your sheet.
If not, you can try typing a question into the search box at the top, like: "Bar chart of Revenue and line chart of Units Sold by Month."
The Explore feature does its best to understand your request and generate a chart that fits. While it's a great starting point and shows where data analysis is headed, it's not always perfect. You may find that it misinterprets your request or creates a chart that still needs manual customization using the steps we outlined earlier. Think of it as a smart assistant that can do about 80% of the work for you, but you still need to check its work and apply the finishing touches.
Best Practices for Effective Combo Charts
Now that you know how to build one, here are a few tips to make sure your combo chart is effective and not misleading.
Keep It Simple: Avoid plotting more than two or three data series. Any more than that and your chart becomes cluttered and impossible to read. The goal is clarity, not complexity.
Use Distinct Colors and Styles: Make it obvious which metric is which. Use a bold color for your bars and a different, but complementary, color for your line.
Always Label Your Axes: It's easy for someone to misinterpret a dual-axis chart if the axes aren’t clearly labeled. Never make your audience guess what they're looking at.
Start Your Y-Axis at Zero: For bar charts, in particular, always start the axis at 0 to avoid exaggerating differences. This gives a more honest representation of the data.
Final Thoughts
Combo charts are a fantastic visualization tool for comparing two related metrics with different scales, all within a single, easy-to-understand graph. By preparing your data carefully and using the Chart editor in Google Sheets, you can transform a plain spreadsheet into a powerful report that uncovers valuable insights.
Features like Google's built-in "Explore" tool hint at a smarter, more automated future for data analysis. We built Graphed because we believe anyone on your team should be able to get answers from their data without learning complex new tools. In Graphed, you connect sources like Shopify or Google Analytics once, then simply ask for what you need in plain English - like "create a dashboard comparing Facebook spend and Shopify revenue by campaign over the last 90 days." Instead of manually building charts and reports, we instantly create a real-time dashboard for you, saving you hours of spreadsheet work.