How to Create a Combo Chart in Power BI

Trying to show how your monthly revenue relates to your marketing spend on a single bar chart can feel like a mess. The revenue numbers might be in the tens of thousands, while your spend is in the hundreds, making one set of bars look tiny and unreadable next to the other. This is exactly where a Power BI combo chart comes in handy, allowing you to visualize two different sets of data cleanly on one graph. This article will walk you through exactly what a combo chart is, when to use one, and how to build your own step-by-step.

When (and Why) to Use a Combo Chart in Power BI

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 primary superpower is displaying two different metrics that have vastly different scales. One metric gets its own Y-axis on the left, and the second metric gets a secondary Y-axis on the right.

This dual-axis approach lets you spot relationships and correlations that would be impossible to see otherwise. It's useful for answering questions where you need to compare volume against a rate or percentage.

Here are a few common scenarios where a combo chart is the perfect tool:

Sales vs. Profit Margin: You might have millions in sales (shown as bars), but your profit margin is a small percentage (shown as a line). A combo chart lets you see if profit margin dips when sales are especially high, perhaps due to discounting.
Website Traffic vs. Conversion Rate: Display website sessions as columns and the session-to-lead conversion rate as a line. You can quickly see if big traffic spikes from a marketing campaign actually resulted in a higher (or lower) conversion rate.
Units Sold vs. Average Price: Track the number of units sold for a product each month with bars, and overlay the average selling price as a line. This can reveal trends in how pricing strategies affect sales volume.
Ad Spend vs. Return on Ad Spend (ROAS): Show your monthly budget spent with columns and the corresponding ROAS as a line. This helps you identify the point of diminishing returns where spending more doesn't necessarily produce a better ROAS.

The key takeaway is this: if you have two metrics measured in different units (like dollars and percentages) or on wildly different scales (like thousands and single digits), a combo chart is your best friend.

Preparing Your Data for a Combo Chart

Before you jump into Power BI, let's talk about the data you'll need. The good news is that the data structure required for a combo chart is simple and intuitive. Your dataset just needs to contain at least three key columns:

A Shared Axis: This is the dimension you want to plot your data against. It's the "over time" or "by category" piece of your analysis. This will form the X-axis of your chart. Examples include a column of dates, months, product categories, or marketing campaign names.
A Column Metric: This is your first numerical value. It's typically a raw count or a high-volume metric that works well as a bar or column. Examples: Total Revenue, Units Sold, Website Sessions.
A Line Metric: This is a second numerical value. It's often a percentage, ratio, average, or another metric that has a different scale from your first one. Examples: Profit Margin %, Conversion Rate, Average Order Value.

For example, a simple spreadsheet for a sales report might look something like this:

Month, Total Revenue, Customer Count "Jan-24", 55430, 85 "Feb-24", 62100, 92 "Mar-24", 89500, 115 "Apr-24", 75300, 101

In this data, a combo chart would use "Month" for the X-axis, "Total Revenue" for the columns, and "Customer Count" for the line. Once your data is loaded into Power BI, you're ready to start building.

Step-by-Step: Building Your First Combo Chart

Creating the chart itself is a straightforward process. For this example, let's assume you have a dataset with monthly sales data including Month, Total Sales, and Profit Margin %.

1. Select the Combo Chart Visual

First, open your report in Power BI Desktop. In the Visualizations pane on the right-hand side, click on the icon for the Line and stacked column chart. This will add a blank chart template to your report canvas.

2. Set Up Your Shared Axis

With the new blank chart selected, look at the fields available under the Visualizations pane. You'll see several "wells" to place your data into: Shared axis, Column y-axis, Line y-axis, and others. Find your date or category field (in our case, Month) in the Data pane and drag it directly into the Shared axis well. Your blank visual will now show the months listed across the bottom.

3. Add a Metric for the Columns

Next, it's time to add your first measure. Since columns are best for showing volume, we'll use Total Sales. Find the Total Sales field in your Data pane and drag it into the Column y-axis well. Just like that, you'll see a standard column chart appear on your canvas, showing your sales for each month.

4. Add an Overlay Metric for the Line

This is where the magic happens. Find your second metric, which for us is Profit Margin %, in the Data pane. Drag this field into the Line y-axis well. Immediately, Power BI transforms your visual. It adds a line that tracks profit margin across the months and, crucially, creates a second Y-axis on the right-hand side specifically for the profit margin percentage. You now have a working combo chart!

Customizing and Formatting for Clarity

A default combo chart is functional, but a little bit of formatting can make it much more professional and easier for your audience to understand. With your combo chart visual selected, click the paintbrush icon ("Format your visual") in the Visualizations pane. This is where you can style every aspect of your chart.

Give Your Axes Meaningful Titles

By default, Power BI may title your axes with things like "Sum of Total Sales." This is technically correct but not very clean. Under the Format your visual tab, go to Y-axis and expand both the primary and secondary sections.

In the main Y-axis section (for your columns), find the Title field and rename it to something clearer, like "Total Sales ($)."
In the Secondary y-axis section (for your line), rename its title to something like "Profit Margin (%)."

Clear, descriptive axis titles remove all guesswork for the viewer.

Adjust Colors to Improve Readability

Good color contrast helps differentiate your two metrics at a glance. In the format settings, you can find options for both Columns and Lines.

Under Columns, you can change the color of the bars to match your company's branding or simply to a neutral color like a medium gray.
Under Lines > Colors, select a color for your line that stands out against the bars. A bright, contrasting color often works best.

Turn On Data Labels

Sometimes, it's helpful for your audience to see the exact value of each bar and line point without having to hover over it. You can enable this by toggling Data labels to "On" in the format settings. Once enabled, you can expand its settings to adjust the font size, color, and positioning of the numbers to ensure they are legible.

Add Markers to Your Line

Sometimes the line on its own can look a little plain and make it difficult to pinpoint the data value for each month. To fix this, head to the Markers section under the format settings. Toggle it to "On". This will add a small shape (like a circle or square) at each data point along your line, making it much easier to track month by month.

After a few simple formatting tweaks, your basic combo chart is transformed into a clear, insightful, and presentation-ready visual that tells a compelling story about your business data.

Final Thoughts

The combo chart is an essential tool in any Power BI user's toolkit, perfect for visualizing two metrics with different scales in one cohesive view. By combining bars and lines, you can uncover relationships in your data that would otherwise remain hidden and provide a much richer context for your reports.

While mastering tools like Power BI is a great skill, we know building every report from scratch can feel time-consuming, especially when you wear multiple hats. That’s why we built Graphed for teams who need fast answers without the steep learning curve. Instead of dragging and dropping fields, you can just describe the report you need - like "Show me our revenue versus profit margin by month as a combo chart" - and Graphed builds a live, professional dashboard for you in seconds. It allows you to connect all your data sources and turn hours of manual chart-building into a quick conversation, freeing you up to focus on acting on the insights.