How to Change Font Size in Power BI

Nothing ruins a great Power BI dashboard faster than text that’s too small to read. You’ve crunched the numbers, built the perfect visuals, and uncovered game-changing insights, but if your team has to squint to see axis labels or KPI cards, your hard work goes to waste. We’ll show you exactly how to control font sizes across your reports, from individual charts to global theme settings.

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Good Reports are Readable Reports

Before jumping into the "how," it’s worth a quick mention of "why." Deliberate font sizing isn’t just about making things look nice, it’s about making your data usable. The right text hierarchy guides your audience's attention, making the report easier to scan and understand at a glance.

Here’s what thoughtful font sizing achieves:

• It reduces misinterpretation. If a user can't clearly read a data label or a category on the X-axis, they might make an incorrect assumption about the data. Clarity is everything.
• It creates a visual hierarchy. Larger, bolder text should be reserved for your most important information, like headline KPIs and chart titles. Smaller text can be used for descriptive details, axis labels, or supplementary notes. This guides the user's eye naturally from the most critical insights to the supporting data.
• It improves professionalism. A report with consistent, well-proportioned fonts looks clean and professional. Inconsistent sizing can make a dashboard feel messy and thrown together, undermining the credibility of the data.

How to Change Font Size for a Single Visual

Power BI gives you granular control over almost every text element on a visual. Let's start with adjusting fonts on a chart-by-chart basis. This is the place to start when you're first designing a report or need to make a one-off adjustment.

First, click on the visual you want to edit. This will bring up three panes on the right side of your screen. You want the one with the paintbrush icon, called Format visual. This pane is your control center for all things cosmetic, including colors, backgrounds, and, most importantly, fonts.

The Format pane is divided into two main tabs: Visual and General. You’ll find text settings scattered between both.

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Changing the Visual Title Font

Your chart title is the first thing people read. Make sure it's clear and prominent.

1. Select your visual.
2. In the Format visual pane, go to the General tab.
3. Expand the Title section.
4. You'll see options for Text (the title itself), Heading, Style, and more. Under the Font subsection, you can change the font family, make it bold or italic, and — most importantly — adjust the Size.

A good starting point for a chart title is around 14pt-16pt, but this will depend on the overall size of your dashboard.

Adjusting Axis Fonts (X-Axis and Y-Axis)

Unreadable axis labels are a common problem. If users can't see the categories or the scale of your chart, the visual loses all meaning.

1. Select your visual.
2. In the Format visual pane, stay on the Visual tab.
3. Expand the X-axis or Y-axis section.
4. In both sections, you'll find two areas to control text: Values (the labels for each data point, like "January," "February") and Title (the descriptive label for the entire axis, like "Month" or "Sales ($)").
5. Expand either Values or Title to find the font size controls. Increase the size until the labels are comfortable to read without straining. A size of 10pt or 12pt is often a good baseline.

Pro-Tip: Turn off the axis title if the context is obvious from the chart title. For example, if your chart title is "Sales Revenue by Month," you probably don't need a Y-axis title that says "Sales Revenue." This simple change can de-clutter your visual.

Editing Data Labels and Legends

Data labels show the exact value of a data point directly on the chart, while the legend helps identify different series in your data. Both need to be legible.

• For Data Labels: Go to the Visual tab, expand Data labels, and look under the Values dropdown to find the font size options. You can also specify the font color here to ensure high contrast against your chart bars or lines.
• For a Legend: Go to the Visual tab and expand the Legend section. Click on Text to access the font options, including the font size.

Special Cases: Cards, Tables, and Slicers

Some visuals have unique names for their text elements.

• Cards: The main number on a card is the Callout value, and the description below it is the Category label. You'll find formatting options for both under the Visual tab of the Format pane. Cards are meant to draw attention, so don't be afraid to make your Callout value large (e.g., 35pt+).
• Tables and Matrices: Managing fonts in tables can feel a bit overwhelming, but the controls are quite powerful. Under the Visual tab, look for the Grid, Column headers, Row headers, and Values sections to control different parts of the table. You can also find Totals to adjust the font size for the summary row.
• Slicers: To change the font size of the items in a slicer list or dropdown, navigate to Slicer settings (for dropdown style) or Values (for list style) under the Visual tab. The slicer's title (header) is controlled under the Slicer header section.

Adjusting fonts one visual at a time is fine for a few charts, but it quickly becomes repetitive for a full report. For report-wide consistency, you need to use themes.

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Work Smarter: Use Themes for Global Font Control

Imagine finalizing a 15-page report and then being asked to increase all the font sizes by 2 points. Doing that manually for every single chart element would take hours. This is where Power BI Themes come in.

A theme is a settings file that applies a consistent design — colors, wallpaper, and text formatting — across your entire report. By changing the font size in the theme, you can update every visual at once.

How to Customize Your Current Theme

1. Go to the View tab in the main Power BI ribbon.
2. In the Themes section, click the dropdown arrow on the gallery.
3. Hover over your current theme and then select Customize current theme.
4. A new window will pop up. On the left, click on Text.

Here you’ll find the global font settings for your report. The defaults are broken down into four main categories, with the default size set to 10pt for everything.

• General: Controls the base text size for most elements, like axis labels and table values. This is the first one you should adjust.
• Title: Governs the default size for all your visual titles. Bumping this to 14pt or 16pt is a good move.
• Cards and KPIs: Affects the callout value on Card visuals and KPI visuals.
• Tabbed headers: Controls the font size for elements like table and matrix headers.

Adjust these sizes, click Apply, and watch as all the visuals in your report update instantly. This is the single most efficient way to manage font sizes and ensure your reports are consistently styled.

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For Ultimate Control: Create a Custom JSON Theme File

For even more granular control, you can create your own theme using a JSON (JavaScript Object Notation) file. This sounds technical, but it’s more straightforward than you might think.

A JSON file is just a plain text file where you define formatting properties. You can specify a default font and size for nearly every element.

Here’s a very simple example of what a theme file targeting font sizes might look like:

{
    "name": "My Custom Font Theme",
    "textClasses": {
        "label": {
            "fontSize": 12,
            "fontFamily": "Segoe UI"
        },
        "callout": {
            "fontSize": 36,
            "fontFamily": "Segoe UI Semibold"
        },
        "title": {
            "fontSize": 16,
            "fontFamily": "Segoe UI Bold"
        },
        "header": {
            "fontSize": 12,
            "fontFamily": "Segoe UI Semibold"
        }
    },
    "visualStyles": {}
}

You can create this in a plain text editor (like Notepad), save it with a .json extension, and then import it into Power BI by going to View > Themes > Browse for themes.

Using a JSON theme file is a favorite trick of professional report developers because it lets them quickly apply brand standards (including specific fonts and sizes) to any new report they create.

Final Thoughts

Fine-tuning text is one of the quickest ways to elevate a good dashboard into a great one. Whether you adjust fonts on a single visual or use a theme to manage your entire report, focusing on readability ensures your audience can easily grasp the valuable insights you’ve uncovered.

We believe data shouldn't be so hard to work with. Tools like Power BI are powerful, but they often require hours of manual formatting just to make a report presentable. Our platform, Graphed, automates that entire process. Just tell us in plain English what you want to see — like "Show me our top-selling products from Shopify this quarter as a bar chart" — and we build a clean, real-time dashboard for you in seconds, no formatting required.