How to Make a Dual Axis Bar Chart in Tableau

Creating a dual axis bar chart in Tableau allows you to compare two different measures with separate scales in the same visualization. It's an incredibly effective way to show the relationship between two distinct metrics, like sales revenue and profit margin, in a single, compact view. This tutorial will walk you through the entire process step-by-step.

What is a Dual Axis Chart and When Should You Use One?

A dual axis chart features two y-axes - one on the left and one on the right - with a shared x-axis. This setup is perfect for visualizing two measures that are on completely different scales.

Imagine wanting to compare your total sales (which are in the tens of thousands of dollars) with your profit ratio (which is a percentage). If you put both on a single axis, the bars for your profit ratio would be so tiny you couldn't even see them next to the towering sales bars. The different scales make a direct one-axis comparison impossible.

A dual axis chart solves this by giving each measure its own scale. One axis represents the dollar amount for sales, and the other represents the percentage for the profit ratio. This lets you analyze trends and relationships between the two metrics side-by-side.

Use a dual axis chart when you want to:

• Compare two measures with different units (e.g., currency vs. percentage, quantity vs. customer satisfaction score).
• Show the relationship between a volume-based metric and a rate-based metric (e.g., number of website sessions vs. conversion rate).
• Visualize metrics that have wildly different magnitudes (e.g., marketing ad spend in the millions vs. number of leads in the hundreds).

Preparing Your Data for Tableau

For this guide, we'll use the Sample - Superstore dataset that comes with every copy of Tableau Desktop. It’s clean, easy to understand, and perfect for learning. If you're using your own data, just make sure it's structured similarly, with at least one dimension (like "Product Category" or "Region") and two measures (like "Sales" and "Profit") that you want to compare.

We will be comparing Sales by Product Sub-Category and also looking at the Profit Ratio for each of those sub-categories.

Creating Your Dual Axis Bar Chart: A Step-by-Step Guide

Follow along with these steps to build your chart from the ground up. We'll start with a simple visualization and layer on the complexity until we have our finished product.

Step 1: Connect to the Sample Superstore Data

First, open Tableau. In the "Connect" pane on the left, find the "Saved Data Sources" section and click on Sample - Superstore to load the dataset.

Step 2: Create a Basic Sales Bar Chart

Let's build the first part of our chart. We want to see total sales for each product sub-category.

• From the "Data" pane on the left, find the Sub-Category dimension and drag it onto the Columns shelf at the top of the workspace.
• Next, find the Sales measure and drag it onto the Rows shelf.

You should now have a simple vertical bar chart showing sales for each sub-category. Great start!

Step 3: Create a Calculated Field for Profit Ratio

The Superstore dataset contains "Profit" and "Sales," but not "Profit Ratio." We need to create that ourselves using a calculated field. A profit ratio shows how profitable a sub-category is, regardless of its total sales volume.

• In the "Data" pane, click the small dropdown arrow at the very top (next to the search bar) and select Create Calculated Field.
• A new window will pop up. Name the field "Profit Ratio".
• In the formula box, enter the following expression:

SUM([Profit]) / SUM([Sales])

• Click OK. Your new "Profit Ratio" measure will appear in the "Data" pane under Measures.

Now, let's format this new field as a percentage so it displays correctly on our chart.

• Right-click on your new Profit Ratio measure in the Data pane.
• Go to Default Properties > Number Format...
• In the window that appears, select Percentage from the list and click OK.

Step 4: Add the Second Measure to the View

Now, drag your newly created Profit Ratio measure from the "Data" pane and drop it onto the Rows shelf, right next to the SUM(Sales) pill.

At this point, Tableau will display two separate bar charts, one stacked on top of the other. The top chart shows Sales, and the bottom one shows Profit Ratio. We're getting closer, but we need to combine them into a single chart.

Step 5: Activate the Dual Axis Feature

This is where the magic happens. To combine the two charts, you need to turn on the "Dual Axis" feature.

• On the Rows shelf, find the green pill for your SUM(Profit Ratio).
• Right-click on it (or click the small downward-facing triangle on the pill with a Windows computer) and select Dual Axis from the dropdown menu.

Instantly, your two charts will merge into one. You'll see the axis for Sales remains on the left, and a second axis for Profit Ratio appears on the right. Tableau might have changed the Mark Type automatically (often to circles), but we'll fix that next.

Step 6: Adjust the Mark Types to Create a "Bar in Bar" Chart

Right now, your chart probably looks a bit jumbled, with bars and circles overlapping. Let's clean this up. A "bar in bar" view is a fantastic way to display this kind of data, with one set of bars nested inside another for easy comparison.

Look at your Marks card. You'll see tabs for "All," "SUM(Sales)," and "SUM(Profit Ratio)." This allows you to control the look of each measure independently.

• Click on the SUM(Sales) tab on the Marks card. From the dropdown menu that likely says "Automatic," select Bar.
• Now, click the Size button and drag the slider to the right to make the sales bars thicker.
• Next, click on the SUM(Profit Ratio) tab on the Marks card. Again, change the Mark Type by selecting Bar from the dropdown.
• Click its Size button and drag the slider to the left to make the profit ratio bars thinner.

You should now see slim profit ratio bars nicely nested inside your wider sales bars. This makes it visually intuitive to see both the total sales volume and the profitability of that volume simultaneously.

Step 7: Final Touches & Formatting

Your chart is functional, but let's make it beautiful and easy to read.

• Colors: On the respective "Marks" cards (SUM(Sales) and SUM(Profit Ratio)), click the Color button to choose distinct colors. Pick a strong color for Sales (like dark blue) and a contrasting, intuitive color for Profit Ratio (like green for positive profit).
• Axis Titles: Right-click on each axis title ("Sales" and "Profit Ratio") and select Edit Axis.... Here you can change the title to be more descriptive, like "Total Sales (USD)" or simply "Profit Margin."
• Tooltips: Hover over one of the bars. The tooltip probably shows both sales and profit ratio data, which can be confusing on a sales-only bar. Go to the Marks card for each measure, click on Tooltip, and edit the text to only show relevant information for that specific measure. This customization makes your chart feel polished and professional.

Alternative Option: A Bar Chart with a Line Chart

One of the most common applications for a dual axis chart is combining bars with a line. This is excellent for showing a trend or a rate against a volume. To change our chart to this format:

• Go to the Marks card.
• Select the tab for your second measure (in our case, SUM(Profit Ratio)).
• Change the dropdown from "Bar" to Line.

Instantly, you have a line representing Profit Ratio moving across the bars representing Sales. This can be a more effective way to spot correlations between the two metrics.

Best Practices and Common Pitfalls

Dual axis charts are powerful, but they can also be misleading if not designed thoughtfully.

• Synchronize Axes... Carefully: If you right-click on the right-side axis, you'll see an option to "Synchronize Axis." This forces both axes to share the exact same scale. For a bar-in-bar chart with different units, you almost never want to do this. The entire point is to have separate scales. Only synchronize axes when your two measures share the same unit and you want to align them perfectly.
• Be Explicit with Labeling: Because the two axes represent different things, it is essential that your axis titles and chart title are clear. No one should have to guess what the left and right axes mean.
• Avoid Clutter: Don't try to cram too much information onto a dual axis chart. At most, you should have two measures. Adding a third or fourth will make the visualization a confusing mess. Keep it simple to keep it powerful.

Final Thoughts

Mastering the dual axis bar chart in Tableau is a huge step toward creating more sophisticated and insightful reports. By giving each measure its own axis, you unlock the ability to compare metrics with completely different scales in a single, coherent visualization, telling a richer data story.

We know that even with a powerful tool like Tableau, building reports can feel like a chore involving endless clicks, calculated fields, and formatting tweaks. We built Graphed to cut through that manual work. Instead of spending time dragging pills and adjusting axes, you just ask a question in plain English. You could say, "Show me sales and profit ratio as a bar-in-bar chart by sub-category," and our AI data analyst would build the visualization for you instantly, streamed directly from your live data sources.