EPUB, Print PDF, or Both? The Files You Actually Need to Self-Publish
For a paperback you need a print-interior PDF (fixed pages, mirrored margins, real gutter). For ebooks you need an EPUB (reflowable text that adapts to any screen). Most authors need both. DOCX is for editors and a few older uploaders, not for the finished book. Don't try to make one file do every job, that's where formatting goes wrong.
Print and ebook are two different objects with two different files. Most formatting pain comes from trying to make one file do both jobs, so start by accepting that you probably need two.
Print-interior PDF
A PDF is fixed. Every page is exactly where you put it. Margins mirror between left and right pages, and the inside margin, the gutter, is wider so text doesn’t vanish into the binding. This is what a printer or a KDP paperback wants, and nothing else will do, because print is physical and the page can’t reflow.
EPUB
An EPUB reflows. There are no fixed pages. The reader’s device decides where lines break based on their chosen font, text size, and screen, which is the whole point of an ebook. That’s also why a print PDF makes a terrible ebook: it locks the layout your reader is trying to change.
For a novel you almost always want a reflowable EPUB, not a fixed-layout one. Fixed-layout is for picture books and cookbooks where the design is the content. Your EPUB needs your cover embedded and working chapter navigation, and that’s most of it.
Which stores want what
- Amazon KDP - print PDF for the paperback, EPUB (or KPF) for Kindle
- IngramSpark - print PDF plus a separate cover PDF, EPUB for the ebook
- Apple Books / Kobo - EPUB
So the honest answer to “which do I need” is usually “both.” A print PDF for the paperback and one EPUB that every ebook store accepts.
Where DOCX fits
DOCX (Word) is not a finished-book format. It’s for two things: sending the manuscript to an editor with track changes, and the handful of older uploaders that still take Word and convert it for you badly. Use it for the workflow, never as the file you publish.
Keep them in sync
The trap with two files is drift. You fix a typo in the print version, forget the ebook, and now your paperback and your Kindle disagree. Galley exports the print PDF and the EPUB from the same book, so both come from one source of truth and always match. Same text, two correct formats.
What each format earns is a separate question. The Kindle royalty calculator covers the ebook side, delivery fee included, and the KDP royalty calculator covers the paperback.
More on publishing
- Standard Manuscript Format, and What Agents Actually CheckThe Shunn manuscript format specification in plain terms: font, spacing, margins, indents, scene breaks, the running header, and the word count that should be rounded.
- Writing Software for Novelists Who Don't Write in EnglishHow to write and typeset a book in Arabic, Persian, Urdu, Hebrew, Hindi, Bengali, Thai, Japanese, Chinese, Korean, Russian, Greek or Vietnamese, which typeface each script gets, and what still needs building.
- Accessible Ebooks and the European Accessibility ActWhat the EAA means for a self-published novel sold in the EU: accessibility metadata, what makes an EPUB accessible, the microenterprise exemption, and the large-print edition nobody makes.