You download an ebook and have a choice: PDF or EPUB. On a Kindle the EPUB-ish format reads perfectly; the PDF requires constant pinch-zooming. On a printed page the PDF looks beautiful and the EPUB doesn't exist. They serve different purposes.
PDF: fixed layout
PDFs preserve the exact look of a printed page. Text in specific positions, images sized as designed, every device shows the same layout. Perfect for textbooks, illustrated books, magazines, technical references where layout is part of the message. Terrible for novel-reading on a phone — you spend more time zooming than reading. Sharing reports, designs, prints? PDF every time.
EPUB: reflowable layout
EPUBs are essentially HTML in a wrapper. Text flows to fit the screen — a paragraph wraps differently on a phone vs a tablet vs an e-reader. Font sizes adjust to your preference; line breaks happen wherever needed. Perfect for novels, biographies, long-form prose. The format Kindles, Kobos, and most e-readers expect natively. Bad for layout-sensitive content because the layout is meant to bend.
Converting between them
Convert PDF to EPUB only when the source is genuinely prose — a novel, an essay collection. Result: better mobile reading. Convert EPUB to PDF when you need to print, share with non-readers, or preserve a specific layout snapshot. Result: looks the same everywhere but loses reflow. Tools for both exist; Flint focuses on PDF but the same source rules apply.
FAQ
Why do publishers offer both?
Different readers want different things. Designers and academics prefer PDF for fidelity. Casual readers prefer EPUB for comfort. Offering both maximises reach.
Does PDF work on Kindles?
Yes, but awkwardly. Kindles display PDFs with limited zoom and no reflow. Native Kindle format (AZW) or EPUB reads far better. Buy or convert to ebook formats for serious reading.
Can I annotate EPUBs like PDFs?
Yes, but less flexibly. Most e-readers allow highlights and notes; full annotation (drawings, sticky notes, shapes) is mainly a PDF feature.
Layout-fixed = PDF. Reflowing prose = EPUB. For everything else PDF-shaped, Flint handles it.