How to Make a Double Bar Graph in Tableau with AI
Building a double bar graph is a fantastic way to compare two sets of data side-by-side, but getting it right in a powerful tool like Tableau can feel tricky at first. This tutorial will walk you through the entire process, step by step, from arranging your data to customizing your final chart. We’ll also touch on how new AI features are changing the way we create these visualizations altogether.
What Exactly Is a Double Bar Graph?
A double bar graph, often called a side-by-side or grouped bar chart, is used to compare a numerical value across two different categorical variables. Instead of a single bar for each category, you get a pair of bars, making direct comparisons incredibly intuitive.
Imagine you want to see how this year's sales compare to last year's sales for each quarter. A double bar graph is perfect for this. One bar would represent 2023 sales, the other would represent 2024 sales, and you’d have a pair of these bars for Q1, Q2, Q3, and Q4.
When should you use one?
Use a double bar graph whenever your main goal is to compare two distinct items within the same category. It's especially useful for:
Comparing Time Periods: Tracking this month’s performance vs. last month’s, or this year vs. last year.
A/B Test Results: Visualizing conversion rates for 'Version A' vs. 'Version B' of a landing page.
Performance Between Segments: Comparing online sales vs. in-store sales for different product lines.
Market Share Analysis: Showing your company's market share against your top competitor's in different regions.
Preparing Your Data for Tableau
Before jumping into Tableau, remember that the quality of your chart depends entirely on the quality of your data. For a double bar graph, your data needs to be structured in a way that Tableau can understand. You don't need a complex layout, a simple "long" format works best.
This means each row should represent a single data point. You should have columns for:
Your primary category (e.g., Month, Quarter, Product).
The category you are comparing (e.g., Year, Campaign Name, Store Location).
The numerical value you are measuring (e.g., Sales, Clicks, Revenue).
Here’s a simple example of what your data might look like in a Google Sheet or Excel file before you import it into Tableau. We'll use this sample data throughout the tutorial, which compares leads generated from two different marketing channels over three months.
Month,Marketing Channel,LeadsJanuary,Google Ads,150January,Facebook Ads,110February,Google Ads,180February,Facebook Ads,145March,Google Ads,210March,Facebook Ads,190
This structure is perfect. Tableau can easily identify "Month" and "Marketing Channel" as dimensions (the things you want to compare) and "Leads" as a measure (the number you want to plot).
Step-by-Step: Creating a Double Bar Graph in Tableau
With your data ready, it's time to build the chart. Follow these steps carefully, and you'll have a professional-looking double bar graph in minutes.
Step 1: Connect to Your Data
Open Tableau and in the "Connect" pane on the left, choose the file type your data is in (e.g., Microsoft Excel, Text File for CSV, or Google Sheets). Navigate to your file and open it. Tableau will display a preview of your data source. Everything should look good if you formatted it like the example above.
Step 2: Create the Basic Bar Chart
Once your data is loaded, you'll land on the worksheet view ("Sheet 1").
First, we need to establish the main axis of our chart. In our example, we want to see performance by month.
Find your primary category, "Month," in the "Data" pane on the left.
Drag "Month" and drop it onto the Columns shelf at the top of the screen.
Next, we need to tell Tableau what value to measure.
Find your measure, "Leads," in the "Data" pane.
Drag "Leads" and drop it onto the Rows shelf.
You’ll now have a simple vertical bar chart showing the total leads for each month. We're halfway there!
Step 3: Split the Bars by Your Second Category
Now it's time to split these single bars into two, one for Google Ads and one for Facebook Ads. This is where the magic happens.
Find your second category, "Marketing Channel," in the "Data" pane.
Drag "Marketing Channel" and drop it directly onto the Color card in the "Marks" pane.
Instantly, your bars will transform into stacked bar charts. Each month's bar will now be segmented by color, one color representing Google Ads and the other representing Facebook Ads. It’s useful, but not quite the side-by-side comparison we're after.
Step 4: Arrange the Bars Side-by-Side
To turn the stacked bars into grouped bars, we just need to make one final drag-and-drop move.
Find the "Marketing Channel" pill that is currently on the Color card.
Drag that "Marketing Channel" pill and drop it onto the Columns shelf, right next to the "Month" pill.
And that’s it! Tableau will immediately rearrange the chart, placing the bars for Google Ads and Facebook Ads next to each other for each month. You now have a double bar graph.
Tableau automatically keeps the color coding, so you can easily distinguish between the two channels. You can edit these colors by clicking on the Color card and selecting "Edit Colors."
Customizing Your Chart for Better Readability
A functional chart is good, but a clear and easy-to-read chart is great. Here are a few tips to polish your work:
Add Labels: Drag the "Leads" measure from the Data pane onto the Label card in the Marks pane. This will display the exact number of leads on top of each bar, saving your audience from having to guess.
Write Clear Titles: Double-click the sheet title ("Sheet 1") and give it a descriptive name like "Monthly Leads: Google Ads vs. Facebook Ads." You can also edit the axis titles by right-clicking on them.
Adjust Bar Spacing and Size: Click on the Size card in the Marks pane. A slider will appear, allowing you to make the bars thicker or thinner to improve the visual balance.
Use Tooltips: Hover over any bar, and you'll see a tooltip with information. You can customize this by clicking on the Tooltip card to add more context or rephrase the information to be clearer.
The AI Shortcut: How Artificial Intelligence is Changing the Game
The manual, click-and-drag method above is the traditional way to build charts in tools like Tableau. It works, but it requires you to know exactly where to click and what "shelves" and "marks" are. As business intelligence evolves, AI is rapidly removing this friction. You don't always have to be the one doing the heavy lifting.
Even within Tableau, you can find features like "Ask Data," which allow you to type a question in plain English (e.g., "show me leads by month and marketing channel as a bar chart") and have Tableau attempt to generate the visualization for you. It's a significant step toward making data analysis more accessible.
However, newer AI-native platforms are taking this concept even further. Instead of being a feature layered on top of a complex tool, natural language is the primary interface. The entire process becomes a conversation. You don't have to learn how to manipulate shelves and pills, you just describe the chart you want to see. This approach eliminates the steep learning curve traditionally associated with powerful BI software.
For example, instead of following the four steps above, you could simply type a prompt like:
“Create a side-by-side bar chart showing leads from Google Ads and Facebook Ads for the last 3 months.”
An AI data analyst would interpret your request, identify the necessary data, and instantly build the correctly formatted double bar graph — all in a matter of seconds. This not only saves an immense amount of time but also empowers team members who aren't data experts to get the answers they need without relying on an analyst.
Final Thoughts
Learning to make a double bar graph in Tableau is an excellent skill for comparing data, and now you have the step-by-step method to do it efficiently. From preparing your data to customizing the final product, the process gives you full control over how you present your insights.
While the manual process is valuable to understand, we designed Graphed to bypass the learning curve entirely. Instead of dragging and dropping, you can just ask questions in plain English to build real-time, interactive dashboards. Connect your data sources like Google Analytics, Facebook Ads, and Salesforce once, and then simply tell us what you want to see – whether it's a double bar graph or a complex funnel analysis – and we'll build it for you instantly.