PDF for e-reader: optimise for Kindle, Kobo and other e-readers

2 min read·25 July 2026

Reading a PDF on an e-reader can be frustrating — text too small, poor layout or files too large. This guide shows how to optimise a PDF for your e-reader so reading becomes comfortable.

Why PDFs work poorly on e-readers

E-readers are designed for reflowable content (text that adapts to the screen size). PDFs are fixed-layout — text is locked to the page. On a small Kindle screen (6 inches) this means: either text too small, or constant scrolling and zooming. The solution: adapt or convert the PDF.

Crop PDF for e-reader screen format

Many PDFs have large margins that waste space on a small screen. Use PDFrust Auto-Trim to automatically remove excess margins. This immediately makes text appear larger without changing the font. Afterwards you can also manually crop via PDFrust Crop for a specific margin.

Trim PDF margins

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Reduce file size for e-reader

E-readers have limited memory and slow processors. A 50 MB PDF loads slowly. Use PDFrust Compress to reduce file size. Choose the middle quality setting — text stays sharp, images slightly more compressed. Aim for under 10 MB for smooth display.

Send to Kindle

Amazon offers the "Send to Kindle" app (Windows/Mac/browser) to send PDFs to your Kindle. Amazon sometimes automatically converts the PDF to Kindle format for better readability. Send to your Kindle email address (@kindle.com) for direct delivery.

Kobo and other e-readers

Kobo e-readers support PDFs via USB connection. Kobo also offers "reflow" for some PDFs but results vary. PocketBook and Onyx Boox have better PDF rendering than Kindle. For academic papers and technical PDFs, a 10-inch e-reader (or tablet) is more comfortable than 6 inches.