Another episode of PBIX A11y Bytes is Live!
Alt Text in Power BI: Practical Guidance, UDFs, and Real Examples
If our dashboards look great but someone can’t see the screen, the insight is gone. Alt text is how we bring that insight back.
Here are the essentials:
1. Text boxes are NOT read by screen readers unless they have alt text.
Even if the text is visible on the canvas, Narrator will only say “Text box” unless we add alt text manually or dynamically.
2. You can test your report with Windows Narrator.
Shortcut: Win + Ctrl + Enter
This instantly turns Narrator on/off so you can hear exactly what a screen‑reader user hears.
3. Static alt text works, but dynamic alt text is better.
Static = limited to 250 characters and doesn’t update with slicers or refreshes.
Dynamic (via DAX or UDFs) = updates automatically and removes the character limit.
4. A structured approach makes alt text easier.
The PBIX A11Y Alt Text Guidance Tool helps you capture:
• category fields
• measures
• filters
• comparisons
• context (units, time period)
• the key insight you want the user to understand
5. UDFs are a game‑changer.
You can package reusable narrative logic into a function and call it across visuals.
I’ve shared a growing library of UDFs you can use today.
5. Hearing the difference is powerful.
In the demo, Narrator goes from “Line chart” to a full, meaningful insight:
trend, values, comparisons, YTD context, all generated dynamically.
Links
- Check out my repository at GitHub – Alt Text UDF Library
- Alt Text Checklist blog post Power BI & European Accessibility Act Part 1 : Implementing Alternative Text
