How to Change Size of Tooltip in Power BI

Tired of Power BI's default tooltips cutting off your data or looking too cramped? You're not alone. While great for quick summaries, the standard tooltips often don't provide enough space for more detailed information. This article will show you exactly how to take control, guiding you through the steps to resize and customize your tooltips for clearer, more user-friendly reports.

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Why Is Tooltip Size So Important Anyway?

Adjusting the size of your tooltips isn't just about making things look prettier - it's about improving the user experience and clarity of your data story. A well-designed tooltip can turn a good report into a great one. Here’s why it matters:

• Better Readability: The most obvious benefit. Cramped text is hard to read. Giving your tooltip content more breathing room prevents users from squinting or, worse, giving up on trying to understand the data.
• Displaying More Information: Sometimes, the default values just aren't enough. A larger tooltip lets you add supplementary details, like variance percentages, narrative context, product images, or small charts that provide a deeper dive without cluttering your main dashboard.
• Preventing Truncation: We’ve all seen it: Product_Category_Nam.... When long category names or descriptions get cut off, the tooltip loses its value. Resizing it ensures your full labels and data points are always visible.
• Creating an Interactive Feel: A custom tooltip can act like a mini-dashboard that appears on hover. This creates a rich, interactive experience where users feel empowered to explore data points on their own terms, discovering insights fluidly and intuitively.

In short, customizing your tooltip size turns it from a simple data label into a powerful component for contextual analysis.

Understanding Your Options: Default vs. Report Page Tooltips

Before diving into the "how," it's essential to know that Power BI offers two main types of tooltips. The method you choose depends entirely on which type you're using.

Default Tooltips

These are the out-of-the-box tooltips that Power BI automatically generates when you drag fields into a visual. They appear as a simple black box displaying the value(s) for the data point you're hovering over. While simple and convenient, your customization options are very limited. You can adjust font sizes and colors, which will indirectly make the tooltip box bigger, but you cannot directly change the canvas dimensions (height and width) of a default tooltip. This is a crucial limitation to understand.

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Report Page Tooltips

This is where the real power lies. A Report Page Tooltip allows you to design a completely custom tooltip by using an entire report page as your canvas. You can add multiple visuals, cards, text boxes, and images, and most importantly, you have full control over the size of the page itself. This is the method we'll focus on for making significant size adjustments and creating truly insightful tooltips.

Method 1: The Quick Fix for Default Tooltips (Adjusting Font Size)

If you only need a minor size increase and don't want to build a whole new report page, slightly increasing the font size of the default tooltip is a fast and easy solution. It makes the text more readable and forces the tooltip box to expand to accommodate it.

Here’s how to do it step-by-step:

1. Select the visual you want to format on your report canvas.
2. With the visual selected, navigate to the Visualizations pane on the right-hand side.
3. Click on the paintbrush icon to open the Format your visual options.
4. Expand the Tooltips section. If you don't see it there, check under the General tab.
5. Here you will see options for Text and Values. Increase the Font size for either (or both) of these options.

As you increase the font size, you’ll notice the tooltip expands to fit the larger text when you hover over the visual. While this is effective for small adjustments, it's not a true resizing solution. For full control, you need to create a custom report page tooltip.

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Method 2: The Ultimate Solution for Full Control (Report Page Tooltips)

This method gives you the freedom to set the exact dimensions of your tooltip and design its content from the ground up. It takes a few more steps, but the payoff is enormous. Let's build one together.

Step 1: Create a New Page for Your Tooltip

First, you need a dedicated page that will serve as your tooltip canvas.

• At the bottom of the Power BI Desktop window, click the '+' icon to add a new page.
• Right-click on the new page tab and select Rename. Give it a descriptive name, like "Sales Details Tooltip," so you can easily identify it later.

Step 2: Enable "Allow use as tooltip"

This is the most critical step. You need to tell Power BI that this page isn't a standard dashboard page but a special page meant to be used as a tooltip.

• Click on an empty area of your new report page to ensure no visuals are selected.
• In the Visualizations pane, click the Format your report page icon (the paintbrush).
• Expand the Page information section.
• Toggle the switch for Allow use as tooltip to On.

Once you do this, you’ll see the page canvas shrink. Don’t panic! This is normal.

Step 3: Customize the Tooltip Canvas Size

Here's where we get to the core goal: changing the size.

• In the same formatting pane, expand the Page size section.
• You'll see the Type is now set to "Tooltip." This is a default preset size.
• To change it, click the "Tooltip" dropdown and select Custom.
• Now, the Height and Width fields become editable. You can enter your desired dimensions in pixels. For example, the default might be 320px width and 240px height. To make it taller and skinnier, you could try 250px width and 400px height. To make a larger square, try 400px by 400px. Play around to find what works for your content.
• Pro Tip: To see what your tooltip will actually look like to the end-user, go to the View tab, click on Page view, and select Actual size. This will display your tooltip canvas at its true 100% scale.

Step 4: Design the Tooltip Content

Now for the fun part. You can add any combination of Power BI visuals onto this canvas. As you add data fields, remember to drag the main category you'll be hovering over into the "Tooltips" data field well at the bottom of the Visualizations pane. This ensures the visuals on your tooltip page are filtered correctly by the data point you hover over on your main chart.

For our "Sales Details Tooltip" example, you could add:

• A Card visual to show the specific Product Name.
• A Multi-row Card to display Total Revenue, Units Sold, and Profit Margin.
• A small Line Chart showing the sales trend for just that product over time.

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Step 5: Apply Your Custom Tooltip to a Visual

Finally, let's connect your new masterpiece to the main visual.

• Navigate back to your main report page.
• Select the chart or visual you want this new tooltip to apply to.
• Go to the Format your visual pane (the paintbrush icon).
• Go to the General tab, then expand the Tooltips section.
• Change the Type from "Default" to Report page.
• Under the Page dropdown, select the tooltip page you just created ("Sales Details Tooltip").

Step 6: Test It!

That's it! Now, go back to your report and hover over a data point on the visual you just updated. Your big, beautiful, custom-designed tooltip will appear, showing all the detailed information you designed, perfectly sized and formatted.

Best Practices for Designing Effective Tooltips

• Don’t Overdo It: Just because you can make your tooltip huge doesn't mean you should. A tooltip should provide quick, contextual information, not a full-blown report. If you have too much data, consider a drill-through page instead.
• Watch Performance: A tooltip with too many complex visuals can be resource-intensive and may slow down your report's hover-response time. Keep it clean and simple.
• Consistent Sizing: Try to use consistent tooltip sizes throughout your report. This creates a cohesive and professional feel for the end-user.
• Consider Placement: A very large tooltip can obscure other important visuals on your page. Test it to make sure it enhances, rather than obstructs, the view.

Final Thoughts

Mastering tooltips takes your Power BI reports from static charts to interactive analytical tools. While the default tooltips serve a basic purpose, creating custom report page tooltips gives you complete control over size, layout, and content, allowing you to provide deeper context exactly where your users need it.

Building dashboards in tools like Power BI is incredibly powerful, but as we’ve seen, it often involves many manual steps and a steep learning curve. At Graphed, we simplify this entire process. We connect directly to your sales and marketing data sources, allowing you to simply ask questions in plain English to build real-time dashboards in seconds. This eliminates the tedious process of formatting visuals one by one, giving you back hours to focus on strategy instead of struggling with report setup. If you're ready to get insights without the hassle, give Graphed a try.