Which ebook format should you choose?
Keep an editable, well-structured source manuscript and create outputs for specific channels. A direct-download workbook may need a designed PDF. The prose companion sold through an ebook store may need a reflowable EPUB. An editor may need DOCX. Trying to make one file serve all three jobs usually gives every audience a compromised experience.
A quick default
Choose EPUB for adaptable long-form reading, PDF for controlled page composition, and DOCX for continued editing. Then verify that the chosen distributor accepts that input and inspect its converted output.
Example: deliver a reading edition and a printable worksheet
A manager-training guide contains prose, a comparison table, and an exercise with space to write. Keep the master manuscript in an editable format. Export the prose as EPUB so readers can enlarge the text. Put the exercise in a companion PDF with deliberate writing space. Send DOCX to the editor who needs to suggest changes.
In the EPUB, replace “complete the box on the next page” with a named exercise link. In the PDF, repeat the instructions beside the writing space. Keep both editions on the same revision number so a corrected example does not remain wrong in the worksheet.
Can you just convert PDF to EPUB?
A conversion can recover text without recovering the original structure. Check for repeated page headers, words split at line endings, columns read in the wrong order, and chapter titles that became body paragraphs. If you have the original DOCX, repair its headings and export from that source. For a scanned PDF, text recognition is a separate step.
How to validate EPUB and preview it for Kindle
- Validate the EPUB structure. Run the file through EPUBCheck. Fix reported errors in the source or export process and generate a new file.
- Read the book in an ebook app. Open the table of contents, jump to the middle chapter, enlarge the text, and inspect your widest table and largest image.
- Check the retailer conversion. For Kindle, use Kindle Previewer and review the converted book before upload.
- Record the exact file. Save its name, revision, test date, apps used, and remaining issues. Test again after changing the export.
EPUBCheck checks conformance to EPUB specifications; it does not establish that the advice is accurate or the design is pleasant to read. As checked on September 7, 2026, KDP lists EPUB, DOCX, and KPF among its manuscript options. It also lists PDF with language restrictions. Follow the current supported-formats page for the edition you are preparing.
EPUB vs PDF vs DOCX: comparison table
| Format | Reader behavior | Best fit | Main tradeoff | Role in workflow |
|---|---|---|---|---|
| EPUB | Content can reflow as screen size and reading settings change; EPUB can also represent fixed-layout publications. | Retail ebooks and long-form reading across different devices. | Page-dependent design, manual spacing, and complex layouts can fail when content reflows. | Reader-facing delivery format. |
| Pages retain their designed geometry and line breaks more predictably. | Printable guides, worksheets, reports, and direct downloads whose page composition matters. | Text can become uncomfortable on small screens, and a visually attractive page is not automatically accessible. | Reader-facing delivery or print-ready artifact. | |
| DOCX | Content remains editable in compatible word processors and can be converted by a publishing workflow. | Author-editor collaboration, review, and manuscript handoff. | Fonts, spacing, tables, and page behavior can vary by application and conversion path. | Working source or accepted platform input, not a universal final reading format. |
EPUB: adjustable text and chapter navigation
The W3C EPUB 3.3 specification defines EPUB as a digital publication format built from packaged web technologies. In a typical reflowable book, the reading system lays out the text for the current viewport and reader preferences. That means the concept of 'page 37' is not stable in the way it is in a PDF.
Good reflowable design depends on semantics: real heading levels, a navigable table of contents, ordered and unordered lists used for their actual purpose, meaningful link text, and images that are not carrying essential information without a text equivalent. It should not depend on repeated spaces, empty paragraphs, manual line breaks, headers, footers, or instructions such as 'see the box on the right.'
- Change the font size and confirm the chapter remains understandable.
- Narrow the viewport and look for clipped images, rigid tables, or horizontal scrolling.
- Use the navigation rather than swiping from the first page to confirm every chapter is reachable.
- Check links, notes, lists, emphasis, scene breaks, and the order in which content is read.
- Inspect both a bright and dark reading theme if the destination supports them; baked-in colors may create contrast failures.
PDF: printable worksheets and fixed pages
A worksheet with spaces to write, a visual report with aligned annotations, or a printable checklist may depend on fixed page boundaries. PDF can preserve that composition. It also asks the author to make more decisions: page size, margins, line length, type size, bookmarks, link treatment, print behavior, and whether the document remains legible on the devices readers actually use.
Do not use PDF merely because it looks identical to the design canvas. Test at realistic screen sizes. A two-column letter-size page that looks elegant on a desktop monitor can require constant zooming on a phone. If most of the book is continuous prose and the layout carries little meaning, reflowable EPUB is usually the more adaptable reader experience.
Prepare a DOCX handoff that survives revision
Use DOCX when an editor needs to change the manuscript or when it is an accepted input to the publishing workflow. Agree which copy is authoritative before sending it. Otherwise the author may keep editing the app while the editor corrects a different document.
- Check the outline in the receiving word processor. Chapter names should be headings, with subheadings nested below them. A bold paragraph may look identical but provide no navigation structure.
- Remove layout workarounds. Replace repeated spaces, empty lines and manually typed page references. Keep essential instructions out of floating text boxes that may move during conversion.
- Send a short handoff note. Name the current revision, requested editing pass, unresolved claims and how corrections should return. Keep image originals alongside the manuscript if the editor needs to replace them.
- Reconcile returned changes once. Apply accepted corrections to the master, then produce new PDF and EPUB files. Do not keep separate editorial fixes only in each final format.
A DOCX file is not a frozen page proof: fonts and layout can vary across applications. Use a PDF proof when you need someone to inspect the specific page composition. KDP's manuscript formatting guide explains its Word-based preparation workflow; other destinations may handle the same file differently.
Six conversion problems and the repair to try first
Record the defect where it appears, then fix the manuscript or export settings that produced it. Repeatedly converting the same unchanged file is unlikely to repair missing structure.
| What you see | Likely cause to inspect | First repair |
|---|---|---|
| Chapter missing from navigation | The title looks large but is a normal paragraph. | Apply the intended heading style, rebuild navigation and re-export. Check that the chapter appears once. |
| Large blank gaps after enlarging text | Empty paragraphs or repeated line breaks used for spacing. | Remove spacer paragraphs. Use paragraph spacing and a deliberate chapter break. |
| A table becomes tiny | Too many columns or a table exported as a picture. | Keep tabular data as a real table where supported; split it into smaller comparisons with repeated row labels. |
| Text disappears in a dark theme | Fixed foreground/background colors or an image with transparent dark text. | Remove unnecessary body-text color overrides. Give the image a readable background and recheck both themes. |
| Footnote opens, but the reader cannot return | A one-way link or incorrect return anchor. | Add or repair the backlink to the referring passage, then test both directions. |
| Every page repeats a header in the prose | A PDF extraction included running headers. | Remove them from the editable manuscript and check every chapter boundary before conversion. |
For Kindle-specific files, compare the result with Amazon's reflowable table guidance and text and note-link guidance. An exporter may require a change outside the writing editor to implement some repairs.
Decide what to send: three concrete delivery packages
A prose guide sold as an ebook
Keep the editable master and prepare a reflowable reading edition accepted by the store. Make chapter names and references navigable, and proof the store's conversion. A separate cover-art file may be needed for the listing; it is a different deliverable from the manuscript.
A workbook for a live workshop
Send the printable PDF, with instructions next to the spaces participants must fill in. Print one copy at the intended paper size. If participants are expected to type answers, test the actual form fields in a PDF reader; blank boxes on a page are not automatically fillable fields. AI Ebook Generator's ordinary PDF export should not be described as an interactive form builder.
A guide with a reusable checklist
Deliver the reading edition and a clearly named companion worksheet. In the ebook, refer to “the Project Handoff Checklist” instead of “the next page.” In the worksheet, repeat the task instructions so it still works when downloaded alone. Track both files in the same revision log.
Before promising a format, test a representative chapter containing your hardest table, image and footnote. Finding that the layout requires a separate edition after formatting the whole book is expensive rework.
Official ebook format specifications
- W3C: EPUB 3.3: normative requirements for EPUB publications and reading systems.
- Amazon KDP: supported ebook manuscript formats: current accepted input formats and platform guidance.
- Amazon KDP Content Guidelines: current content responsibilities for that distribution channel.
Prepare images and manuscript structure
How to create an ebook
Place the format decision inside a complete editorial and release workflow.
Images in ebooks
Plan visual purpose, alternatives, captions, rights, and cross-screen testing.