Custom Fonts in Power BI (and what to watch out for)

All 26 fonts, in the order the dropdown:
Arial
Arial Black
Arial Unicode MS
Calibri
Cambria
Cambria Math
Candara
Comic Sans MS
Consolas
Constantia
Corbel
Courier New
DIN
DIN Light
Georgia
Lucida Sans Unicode
Segoe UI
Segoe UI Light
Segoe UI Semibold
Segoe UI Bold
Symbol
Tahoma
Times New Roman
Trebuchet MS
Verdana
Wingdings.

Download your brand font and install it locally. Right-click the .ttf or .otf file and choose "Install for all users" if you have admin rights.

Power BI reads fonts from the operating system, so the font has to be sitting on the machine that renders the report. That one detail causes most of the trouble in Step 5. This is also one of the main cons for custom fonts in the first place.


Step 2: Export Your Current Theme

In Power BI Desktop, open View > Themes. You'll see Download current theme near the bottom, and on a fresh report it will be greyed out

• Open Customize current theme, give the theme a name or change any setting, hit Apply. It's now a custom theme, and Download current theme is available.
• Or pick any non-Default built-in theme from the gallery first. The restriction is only on Default, so anything else would work. 

Either way you end up with a JSON file that already contains a palette.

Open the file in VS Code or Notepad. There are two places you can set fonts, and they behave differently.

textClasses is the clean option. It sets the font for whole categories of text at once:

Watch the property name. Inside textClasses it's fontFace, not fontFamily. Get that wrong and the theme still loads without complaint, it just ignores your font.

Four classes cover most of the report. callout is card numbers, title is visual titles, header is table and matrix column headers, label is data labels and axis text.

Look at the commas in that font list. Power BI writes your font name straight into CSS, so you can hand it a fallback stack exactly like you would on the web. First available font wins, and any name with a space goes in single quotes. Without one, viewers who don't have your font can end up with Times New Roman (default fallback), so always end the stack with a built-in font.

visualStyles is the surgical version. Use it when a single visual needs something different. The property there is fontFamily:

Two things to keep in mind:

• The font name has to match exactly what Windows registered. Open Windows Settings > Fonts and copy it from there. "Roboto Semibold" and "Roboto SemiBold" are different strings, and Power BI will not tell you which one you got wrong. So always double check if it works/shows.
• If you type a name that doesn't exist, there's no error message. The theme loads, the report renders, and you get the fallback.

View > Themes > Browse for themes, pick your JSON, done. Titles, headers, labels and card numbers should all switch immediately.

If nothing changed, the font name is wrong. Go back to Step 3 and copy it from Windows Settings rather than from the font file name.

Custom fonts render only when the font is installed. I publish the same report and opened the same visual three times: on my own machine it showed Roboto, on a colleague's PC it didn't, and on my phone it didn't either.

Power BI gives you no warning about this. It just substitutes and moves on. Before you ship anything, open it once somewhere that doesn't have your font installed, check if fallback works correctly.

• Always ship a fallback stack. It costs one comma in the theme file. You still don't get your brand font, but you get to decide what viewers see instead of Times New Roman (which can bring severe consequences to formatting and cause misalignment).

• Pick the closest safe font. Segoe UI, Tahoma, Verdana, Georgia, and Trebuchet MS are on every machine (default MS fonts), so everyone sees the same thing even if it isn't your brand font. This is what I'd recommend for anything shared widely, without a possibility to assure font is installed.
• Deploy the font to every viewer's machine. This works where IT manages the devices and can push fonts through Intune or Group Policy. In some companies every machine comes with full braded assets preinstalled. For external clients or public reports, it isn't realistic at all.
• Use paginated reports for anything printed. Report Builder embeds fonts into the PDF, so it comes out right.

* TIP
There's also the low-tech workaround: put the page title text in an image background. It isn't elegant (or flexible), but for single report/page it bring the branding back and works on every machine.