Can Immersive Reader open a PDF?
No. PDF is not an accepted input format for Immersive Reader, and there is no OCR step anywhere in its API. This is not a limitation of a particular app — it is the documented behaviour of the Immersive Reader SDK.
What Immersive Reader actually accepts
The Immersive Reader SDK reference lists the MIME types it will render: text/plain, text/html, application/mathml+xml and the .docx Word format. application/pdf does not appear in that list.
Because Immersive Reader is a viewer that a host application passes content into, it needs text it can already read. It has no mechanism for turning a page image into text, so a PDF containing scanned pages is outside its scope twice over: the container is not supported, and the content is not text.
Verify it yourself in the Immersive Reader SDK reference.
Why this catches people out
Immersive Reader is genuinely good at what it does, and it is free inside Word, OneNote, Teams and Edge. So the reasonable assumption is that it will read whatever you put in front of it. It will not.
The gap shows up with exactly the documents that cause the most trouble: a photocopied course reading, a benefits letter scanned to PDF, a form someone photographed and emailed. Those arrive as images. Immersive Reader has nothing to work with.
What reads a scanned PDF instead
You need something that performs optical character recognition and then reads the result. Options include a dedicated OCR product, a screen reader with OCR built in, or an assistant that does the recognition itself.
Darvy reads scanned, image-only PDFs directly, and keeps tables in their row and column structure rather than flattening them into a run of text. There is a step-by-step walkthrough in how to read a scanned PDF when you are blind.
Related questions
Does Immersive Reader support PDF files?
No. The documented MIME types Immersive Reader accepts are text/plain, text/html, application/mathml+xml and .docx. application/pdf is not among them, and the SDK includes no OCR step.
Can Immersive Reader read a scanned document?
No. Immersive Reader renders text that a host application supplies to it. A scanned page is an image, and Immersive Reader has no optical character recognition of its own.
Is there a file size limit in Immersive Reader?
Yes. The SDK documents a 50 MB limit on the content passed to it.
What can read a scanned PDF aloud?
A tool that performs OCR before reading. Darvy reads scanned, image-only PDFs directly on Windows 10 and 11, alongside JAWS, NVDA or Narrator.
More comparisons and guides are collected in the Darvy resources hub.