EPUB Formatting Best Practices for Fiction and Nonfiction

EPUB is the format underlying nearly every ebook platform, even Amazon, which converts EPUB to its proprietary KFX format internally. A well-built EPUB renders cleanly across Kindle, Kobo, Apple Books, and the dozens of retailers reached through aggregators like Draft2Digital. A poorly built one can look fine in one reading app and break in another, missing chapters in the table of contents, fonts that don't display, images that overflow the screen, or text that doesn't reflow properly when a reader changes font size.

This guide covers what makes an EPUB well-built, from its underlying structure to the details that matter for fiction and nonfiction specifically.

What an EPUB actually is

An EPUB file is a ZIP archive containing a specific folder structure: XHTML files (your actual content, one or more per chapter or section), CSS files (styling), image files, font files (if embedded), and several metadata and navigation files that describe the book's structure to reading apps.

The two files that matter most for navigation and reader experience:

The OPF (package) file: lists every file in the EPUB and their reading order (the "spine"). This tells reading apps what order to present your content in.

The navigation document (nav.xhtml in EPUB 3, or the NCX file in EPUB 2): defines your table of contents, the list readers see when they tap "Contents" in their reading app, and that some apps use for "go to chapter" navigation.

Most authors never need to edit these files directly, formatting tools generate them automatically, but understanding that they exist explains why certain things (like a missing table of contents entry) happen: usually, a heading wasn't marked with the right tag, so it wasn't picked up when the navigation document was generated.

Reflowable vs. fixed-layout EPUB

Reflowable EPUB is the format used for the vast majority of books: text flows based on the reader's screen size, font size preference, and orientation. A reflowable EPUB might display 2 paragraphs per "page" on a phone and 5 on a tablet, the content adapts to the device.

Fixed-layout EPUB preserves exact page layouts, similar to a PDF but still using EPUB's underlying format. This is used for children's picture books, heavily illustrated books, and comics, where the precise placement of text relative to images matters and can't be left to reflow.

For standard fiction and nonfiction (the vast majority of self-published books), reflowable EPUB is the right choice. Fixed-layout EPUB requires a fundamentally different design approach and is generally only necessary for illustrated children's books and similar visually-precise formats.

Semantic markup: the foundation of a good EPUB

The single most important practice in EPUB formatting is using semantic HTML tags correctly, meaning tags that describe what content is, not just how it should look.

Headings: chapter titles should be marked with heading tags (<h1> for the book title or top-level division, <h2> for chapter titles, depending on your structure). This is what allows reading apps to automatically generate a working table of contents and "go to chapter" navigation. If a chapter title is just a large, bold paragraph of text rather than a heading tag, it won't appear in the navigation, even if it looks identical on the page.

Paragraphs: body text should be in <p> tags, not line breaks (<br>) used to simulate paragraph breaks. This affects how text reflows and how assistive technology (screen readers) interprets your content.

Emphasis vs. styling: use <em> for emphasized text (which typically renders as italic) and <strong> for strongly emphasized text (typically bold), rather than wrapping text in <span> tags with CSS styling applied directly. Semantic tags carry meaning that styling-only tags don't, which matters for accessibility and for how some reading apps handle text-to-speech.

Why this matters across platforms: Amazon's KFX conversion, Kobo's renderer, and Apple Books' renderer all rely on this semantic structure to generate navigation, apply default styling consistently, and support accessibility features. An EPUB built on semantic markup "just works" across platforms; one built on visual hacks (using paragraph styling to fake headings, for instance) breaks in ways that are hard to predict and debug.

CSS best practices for EPUB

CSS controls the visual presentation of your EPUB's content, fonts, sizes, spacing, alignment, and more. A few principles keep your CSS working well across reading environments:

Use relative units, not fixed pixel values: font sizes, margins, and spacing should use relative units (em, rem, percentages) rather than fixed pixels. Reflowable EPUB needs to adapt to different screen sizes and reader font-size preferences; fixed pixel values don't scale with those preferences and can produce text that's too large or too small relative to the rest of the page.

Avoid absolute positioning: CSS properties that position elements at fixed coordinates don't translate well to reflowable content, which by definition doesn't have fixed coordinates. Reserve absolute positioning for fixed-layout EPUBs only.

Keep your CSS simple and well-organized: a single, well-organized stylesheet that defines styles for your headings, body text, block quotes, scene breaks, and other recurring elements is easier to maintain and debug than scattered inline styles throughout your content files.

Test your CSS across multiple readers: a style that renders perfectly in one reading app might render slightly differently in another due to differences in how each app's renderer interprets CSS. This is normal and expected; the goal is "looks good and is readable everywhere," not "renders pixel-identically everywhere."

Font embedding

Embedding custom fonts in your EPUB ensures readers see your chosen typography rather than their device's default font. But font embedding has more nuance than it might first appear.

Licensing: most commercial fonts require an embedding license, separate from a license to use the font in design software. Before embedding any font in a published EPUB, confirm its license explicitly permits embedding in distributed ebook files. Many fonts designed for web or print use don't automatically include ebook embedding rights.

Font formats: EPUB supports several font file formats (OTF, TTF, WOFF). Most modern EPUB creation tools handle the appropriate format automatically; if you're embedding fonts manually, check which formats your target platforms support.

Font fallbacks: always specify a fallback font family in your CSS (a generic serif or sans-serif) in case the embedded font fails to load on a particular device for any reason. This ensures readers see reasonable typography even in edge cases.

When not to embed fonts: if your book uses entirely standard fonts that reading devices already provide good equivalents for, font embedding may not be necessary, and skipping it keeps your file size smaller. Embedding matters most when your design relies on a specific, non-standard typeface for its intended effect.

Images in EPUB

Cover image: your EPUB's cover image is typically referenced in the OPF file with a specific metadata flag identifying it as the cover, which reading apps use for library display and store listings. Most formatting tools handle this automatically when you designate your cover during export.

Image resolution and file size: images should be high enough resolution to look sharp on high-density displays (retina-class tablets and phones) but not so large that they bloat your EPUB's file size unnecessarily. A balance of roughly 1,500-2,000 pixels on the longer dimension for interior images, compressed to a reasonable file size, works well for most purposes.

Image scaling in CSS: images should be set to scale relative to their container (using percentage-based width in CSS) rather than fixed pixel dimensions, so they display appropriately across different screen sizes without overflowing or appearing too small.

Alt text: every image should have descriptive alternative text (the alt attribute), which is read aloud by screen readers and displayed if an image fails to load. For decorative images that convey no informational content (a simple divider graphic, for instance), an empty alt attribute (alt="") is appropriate, signaling to assistive technology that the image can be skipped.

Table of contents and navigation

EPUB 3's navigation document defines your table of contents. A well-structured nav document should:

• List every chapter (and major front/back matter section) in reading order
• Use the same heading text that appears in the book itself, so readers recognize the correspondence
• Not include every minor subheading (a TOC with 200 entries because every scene break got a heading is unwieldy; reserve TOC entries for chapter-level and major section divisions)

Front matter and back matter in the TOC: whether to include front matter (title page, copyright page, dedication) and back matter (acknowledgments, about the author) in your visible table of contents is a stylistic choice. Many fiction EPUBs list only chapters plus key back-matter items (like "About the Author" or a link to the next book), keeping the front matter present in the file (and in the reading order) but not cluttering the navigation.

Special formatting in EPUB

Scene breaks

Scene breaks (a visual indicator of a shift in time, location, or point of view within a chapter, without a full chapter break) are typically rendered as a centered symbol or set of characters (asterisks, a small ornament, or simply extra white space). In EPUB, scene breaks should be marked with a distinct CSS class so they render consistently and don't get confused with paragraph breaks during reflow.

Drop caps

Drop caps (an enlarged first letter of a chapter) can be implemented in EPUB CSS using the ::first-letter pseudo-element, though support and rendering quality vary across reading apps. Apple Books tends to render CSS drop caps with high fidelity; some e-ink readers render them less precisely. Testing your drop cap implementation across a few reading environments before finalizing is worthwhile if drop caps are part of your design.

Block quotes and extracts

Longer quoted passages, epigraphs, or extracts (common in nonfiction, and in fiction for epigraphs at the start of chapters) should use the <blockquote> tag with appropriate styling, not manual indentation via spaces or tabs, which doesn't translate to EPUB's reflowable structure.

Footnotes and endnotes

EPUB supports linked footnotes and endnotes using internal hyperlinks: a superscript number or symbol in the text links to the note's content elsewhere in the file (often at the chapter end or in a dedicated notes section), and the note links back to the text. EPUB 3 also has a specific semantic structure for footnotes (using epub:type attributes) that some reading apps use to display footnotes in a popup rather than navigating away from the page, a much better reading experience for footnote-heavy nonfiction.

Accessibility in EPUB

EPUB accessibility has become increasingly important, both because it's the right thing to do for readers with visual or other impairments, and because some retailers and library platforms increasingly check for accessibility features.

Reading order: your EPUB's content should follow a logical reading order matching how a sighted reader would experience the book, which screen readers rely on for narration.

Heading structure: proper heading hierarchy (covered above) is also an accessibility feature, screen reader users can navigate by headings, jumping between chapters efficiently.

Alt text for images: as covered above, meaningful alt text for informational images and empty alt text for decorative images.

Language metadata: your EPUB's metadata should specify the language of the content, which screen readers use to select the correct pronunciation rules.

Color contrast: if your design uses custom colors for text (uncommon in standard fiction and nonfiction, but used in some specialty books), ensure sufficient contrast between text and background colors for readers with low vision.

Most of these accessibility practices are also simply good EPUB practices; following the structural and semantic guidance throughout this guide largely produces an accessible EPUB as a byproduct, rather than requiring separate accessibility-specific work.

Fiction-specific EPUB considerations

Chapter structure: most fiction EPUBs use one XHTML file per chapter (or sometimes group several short chapters into one file), each starting with a chapter heading marked as <h2> (or appropriate level), followed by the chapter's body text.

Dialogue formatting: standard fiction dialogue conventions (quotation marks, new paragraph for each speaker change) translate directly to EPUB without special handling, as long as paragraphs are properly tagged.

Series information: many fiction EPUBs include a "Also by [Author]" page in the back matter, often with links to other books' product pages (though linking to external retail pages from within an EPUB has platform-specific considerations; some platforms restrict outbound links in certain contexts).

Nonfiction-specific EPUB considerations

Tables: EPUB supports HTML tables, and most modern reading apps render them reasonably well, though complex tables (many columns, nested structure) can be challenging on small screens. For nonfiction with data-heavy tables, consider whether the information could also be presented as a list or simplified for better small-screen readability, in addition to the table.

Sidebars and callout boxes: nonfiction often includes sidebars, tips, or callout boxes visually distinguished from body text. In EPUB, these are typically implemented as a <div> with a distinct CSS class and styling (a border, background color, or different font), which reflows along with the rest of the content.

Index: a traditional back-of-book index (with page numbers) doesn't translate meaningfully to EPUB, since EPUB has no fixed page numbers. Some nonfiction EPUBs omit the index entirely, include the index as linked terms, or note that an index is available in the print edition.

Numbered lists and procedures: how-to and instructional nonfiction often relies on numbered steps; EPUB's ordered list (<ol>) tag handles this natively and reflows correctly.

Validating and testing your EPUB

EPUBCheck: an open-source validation tool used (in some form) by many platforms internally to check EPUB files for structural errors. Running your EPUB through EPUBCheck before uploading catches issues that might not be visible in a casual preview but could cause platform-specific rejections or rendering problems.

Kindle Previewer: Amazon's free tool shows how your EPUB will look after conversion to KFX for various Kindle devices and apps. This is the closest approximation to how your book will appear on Kindle without uploading to KDP directly.

Platform-specific previews: KDP, Kobo Writing Life, and other platforms typically offer a preview step before final publication, showing how your file renders within their system. Use these previews as a final check even after validating with EPUBCheck and Kindle Previewer.

Common EPUB errors and how to avoid them

Issue	Likely cause	Fix
Missing table of contents entries	Chapter titles not marked with heading tags	Use proper <h1>/<h2> tags for chapter titles
Text too large or too small on some devices	Fixed pixel font sizes in CSS	Use relative units (em, rem, %)
Images overflowing the screen	Fixed pixel image dimensions	Use percentage-based widths in CSS
Embedded font not displaying	Font format unsupported by a platform, or licensing issue	Use widely-supported formats and confirm embedding license
Inconsistent scene break appearance	Scene breaks styled inconsistently or via manual spacing	Use a dedicated CSS class for scene breaks
EPUB rejected during upload	Structural validation errors	Run EPUBCheck before uploading

Frequently asked questions

Do I need to learn HTML and CSS to create a good EPUB?

Not necessarily. Formatting tools like LiberScript generate semantically correct, well-styled EPUB files from your manuscript without requiring you to write code. Understanding the principles in this guide helps you recognize issues and communicate with formatting tools or services, but hand-coding isn't required for most authors.

Why does my EPUB look different on different devices?

This is expected and normal. Reflowable EPUB adapts to each device's screen size and the reader's font preferences. As long as the text is readable, properly structured, and your design elements (headings, scene breaks, etc.) render consistently in their intended style, minor visual differences between devices aren't a problem.

Can I include hyperlinks in my EPUB?

Yes, internal links (to other parts of your book, like footnotes or a table of contents) and external links (to a website) are both supported. Some platforms have policies about what kinds of external links are permitted (particularly links to other retailers or competing storefronts), so check current platform policies if your links point outside your own website or email signup.

What's the difference between EPUB 2 and EPUB 3?

EPUB 3 is the current standard and supports more features (better accessibility support, more robust navigation, support for audio/video in some contexts, though rarely used in standard books). Most modern formatting tools produce EPUB 3 files, which are backward-compatible with EPUB 2 readers for standard text content.

Should my EPUB and print interior have the same chapter structure?

Yes, the underlying content structure (chapters, sections, front and back matter) should be consistent between your EPUB and print interior, even though the visual styling differs by medium. This consistency also makes future updates easier, since both versions are built from the same source content.

The bottom line

A well-built EPUB comes down to using semantic markup correctly, writing CSS that adapts to reflow rather than fighting it, embedding fonts and images responsibly, and validating before you publish. These practices produce files that render well across Kindle, Kobo, Apple Books, and every other major platform, and that are more accessible to readers using assistive technology as a natural consequence of being well-structured.

For how your EPUB fits into a broader multi-platform strategy, see our guide on multi-platform formatting. For the differences between print and ebook formatting more broadly, see our guide on KDP print vs. ebook formatting. To generate a well-structured EPUB from your manuscript automatically, get started in LiberScript.