How to Make a Combo Chart in Google Sheets with ChatGPT

Creating a chart that displays two different types of data, like revenue and website traffic, can feel tricky in Google Sheets. You're trying to compare numbers with completely different scales - tens of thousands of dollars next to hundreds of sessions. This is exactly what a combo chart is for, and this guide will show you how to build one, using ChatGPT to streamline the entire process.

What is a Combo Chart, and Why Use One?

A combo chart, or combination chart, is a single visual that combines two different chart types, most commonly a column chart and a line chart. Its main job is to help you visualize a relationship between two metrics that are measured on different scales.

Trying to plot revenue (in thousands) and conversion rate (in single-digit percentages) on the same Y-axis just doesn't work. The conversion rate line would look like a flat line at the bottom, and any variation would be impossible to see. A combo chart solves this by giving you a second Y-axis, so each metric gets its own scale while sharing a common X-axis (like time).

You'd want to use a combo chart to answer questions like:

• How did our marketing ad spend (line chart) impact sales revenue (column chart) last quarter?

• Is there a connection between the number of new leads we generate (column chart) and our sales team's close rate (line chart)?

• How does our website's user traffic (column chart) relate to our monthly sign-ups (line chart)?

By layering these two data points, you get context that two separate charts just can’t provide. You can spot trends, identify correlations, and tell a much more complete story with your data.

Step 1: Get Your Data Ready in Google Sheets

Before you can build any chart, your data needs to be clean and structured logically. For a combo chart in Google Sheets, aim for a simple, clear layout.

Your first column should always contain your primary dimension - the thing you are measuring against. This is usually a time-based category like "Month," "Date," or "Quarter," but it could also be product categories or campaign names.

The columns to the right of your dimension will contain the numbers, or metrics, you want to visualize. For a standard combo chart, you'll need at least two metric columns.

Here’s a practical example showing monthly revenue, total website sessions, and new customers. Notice how "Revenue" is in the thousands, while "New Customers" and "Sessions" are in the hundreds and tens of thousands, respectively - perfect for a combo chart.

Your sheet should look something like this:

With your data organized this way, you're ready to start building the chart a couple of different ways.

Step 2: How to Manually Create a Combo Chart in Google Sheets

Understanding the manual process is helpful because it shows you exactly what steps ChatGPT is automating for you. Here’s how you would create a combo chart the traditional way:

1. Highlight Your Data: Click and drag to select the entire data range you want to use, including the headers.

2. Insert Chart: Navigate to the top menu and click Insert > Chart.

3. Select "Combo chart": A chart will appear, along with the Chart editor pane on the right. Google Sheets will try to guess the best chart type, but it often defaults to something else. In the chart editor, under the Setup tab, click the "Chart type" dropdown box. Scroll down to the bottom and choose Combo chart.

4. Customize Your Series: This is the most important step. Your metrics (e.g., "Sales Revenue" and "Website Sessions") need to be assigned the correct chart type and axis. Navigate to the Customize tab in the chart editor and click on the Series section.

5. Format Each Series: By default, Google Sheets will apply the same chart type to all series. Let's say you want "Sales Revenue" to be expressed as columns. Use the series dropdown to find "Sales Revenue" and ensure "Columns" is selected as the type.

6. Use the Second Axis: Now, for the other metric. Select "Website Sessions" from the series dropdown. To display it clearly, change its chart type to Line and, critically, use the "Axis" dropdown below it to change it from Left axis to Right axis. You will immediately see the chart transform as the "Website Sessions" line adjusts to its own scale on the right-hand side.

7. Add Titles and Labels: Finally, finish up by going to the Chart & axis titles section in the editor to give your chart a clear title and label your Y-axes (e.g., "Sales Revenue ($)") so your audience knows what they're looking at.

This process works perfectly well, but it involves quite a few clicks. It's easy to get lost in the menu, especially when assigning series to the correct axis. Now let’s look at how AI can do the heavy lifting.

Step 3: Using ChatGPT to Create Your Combo Chart Much Faster

Here’s where things get interesting. ChatGPT can't click around in your Google Sheet, but it is excellent at writing Google Apps Script - short snippets of code that can automate tasks inside of Google products. You don’t need to be a developer to do this. You just need to know how to ask the right way.

Part A: Opening the Script Editor in Google Sheets

First, you need to open the tool where you'll paste the code. In your Google Sheets menu, click Extensions > Apps Script. A new browser tab will open with a code editor. It’s a clean and simple interface. You'll see a file named Code.gs with a default function inside it. Just delete all of the default template text to start with a blank slate.

Part B: Crafting Your Prompt for ChatGPT

Your success depends on your prompt. Don't be vague. Be extremely specific and tell it exactly what you want it to build.

A good prompt for creating a combo chart should include:

• The name of the sheet where your data is (e.g., "Sheet1").

• The exact data range (e.g., "A1:C8").

• Which column is the X-axis.

• Which columns are your Y-axis data series.

• The chart type for each series (e.g., columns for sales, line for traffic).

• Which series should be on the right axis.

• Any desired customizations like a chart title or axis labels.

Here is a template you can use. Just fill in your own details:

“I have data in a Google Sheet named 'Sheet1'. The data is in the range A1:C8.Column A contains the "Month" and should be the X-axis.Column B is "Sales Revenue" and should be a column chart on the default left Y-axis.*Column C is "Website Sessions" and should be a line chart pinned to the right Y-axis.Could you write a Google Apps Script to build this combo chart? Please give the chart the title "Monthly Revenue vs. Website Sessions." The left axis title should be "Sales Revenue ($)", and the right axis should be "Total Sessions."”

Part C: Generating and Running the Code

Copy your prompt and paste it into ChatGPT. It will generate a block of Google Apps Script code for you. Don't worry if you don't understand what every line does. The code will look something like this:

Here's how to use it:

1. Copy the entire code block from ChatGPT.

2. Paste it directly into the blank Apps Script editor you opened earlier.

3. Click the Save project icon (it looks like a floppy disk).

4. Click the Run button (it looks like a play button ▶).

The first time you run a script, Google will ask for your permission to let the script access your spreadsheet data. This is a standard security step. You will have to click "Review permissions," select your Google account, and click "Allow" on the confirmation screen.

Once you’ve given permission, just switch back to your Google Sheet. Your fully-formed combo chart will be waiting for you, placed neatly on your sheet.

Step 4: Customizing Your ChatGPT-Generated Chart

The code gets you almost all the way there, but you might want to adjust colors, change the background, or add trendlines. The great thing is that a chart created with code is still just a regular Google Sheets chart.

You can double-click the chart to open the Chart editor on the right and make any final tweaks using the same options described in the manual process. Change the color of your line series to red, fatten the line thickness, or change fonts - it's all easily accessible.

Alternatively, you can skip the manual tweaks and simply ask ChatGPT for modifications. You can use follow-up prompts like:

“Great, that worked! Now please modify the script to make the line chart color bright blue and the columns dark gray.”

ChatGPT will adjust the script's 'options' section, and you can simply copy, paste, and run it again to get the updated version.

Final Thoughts

Creating a combo chart is a fantastic way to tell a detailed story with your data by comparing two different metrics in one place. While the manual method in Google Sheets provides all the tools you need, leveraging ChatGPT to write an Apps Script can save you precious time and avoid all the manual clicking through customization menus.

Manually building reports and charts, even with AI prompts to help, still requires you to bring all your data into one place first. When all your marketing and sales data lives in different apps like Google Analytics, Shopify, QuickBooks, and Salesforce, getting it all into a spreadsheet is still a massive time-drain. At Graphed, we built our tool to eliminate that exact pain point. Instead of wrangling CSV files and writing scripts, you can simply connect your data sources once, then describe the charts and dashboards you need in plain English. This turns hours of tedious reporting work into a simple, 30-second conversation, giving your time back for more important things.