Power BI App Custom page size not fitting

Hi Anonymous,

Thank you for reaching out to the Microsoft Community Forum.

It’s not anything you are doing wrong, this is actually a limitation of Power BI Apps. The App viewer doesn’t auto-scale custom canvas sizes, so large layouts like your 3500×1600 page will always look zoomed in there, even though they fit correctly in the regular Power BI Service. Only the standard page sizes get proper scaling inside Apps.

There isn’t a setting in Desktop or the App that can fix this today. The only workarounds are reducing the canvas width, redesigning to a standard size or viewing the report directly in the Service instead of through the App.

If keeping the custom layout is important, it’s worth submitting an idea to Microsoft.

Fabric Ideas - Microsoft Fabric Community
You can submit something like: Power BI Apps should auto-scale reports that use custom canvas sizes, just like they do in the regular Power BI Service. Today, custom page sizes appear zoomed or cropped inside Apps because they don’t resize to fit the viewer. Enabling proper scaling would make complex, wide layouts usable without redesigning them.

 
Hope the above provided information help you resolve the issue, if you have any further concerns or queries, please feel free to reach out to us.
Regards,
Community Support Team.