Sell your ebook as EPUB. Use PDF for the print edition and for anything where the page itself is the product.
The usual reason given for this, that PDF is inaccessible, is wrong, and worth correcting because a wrong reason leaves you unable to judge the exceptions. The real arguments are fixed pagination and retailer acceptance.
"PDF Is Inaccessible" Is Not True
The Library of Congress states the opposite:
"Depending on implementation, PDF files can strongly support accessibility. One component is logical structure features that allow applications that produce PDF files to choose what structural information to include and how to represent it."
Tagged PDF supports "automatic reflow of text and associated graphics to fit a page of a different size than was assumed for the original layout" and "making content accessible to people who rely on assistive technology."
There is even a formal accessible profile. PDF/UA-1, published as ISO 14289-1, is described by the Library of Congress as "a constrained form of Adobe PDF 1.7... intended to ensure accessibility and support for assistive technology, such as screen readers", requiring that "Content shall be marked in the structure tree with semantically appropriate tags in a logical reading order" and that images "shall be given a Figure tag that includes alternative or replacement text."
So an accessible PDF is entirely possible. The honest framing is different: an accessible PDF requires a deliberate tagging pass that a default export does not produce, whereas an EPUB's accessibility comes from the HTML semantics you are already writing. One is work you must add; the other is work you get for free by using the format correctly.
The Real Argument Is Reflow
This is where PDF genuinely loses for ebook reading, and it is a specification-level problem rather than an opinion.
WCAG 2.2's Reflow criterion, at Level AA, requires that content be presented "without requiring scrolling in two dimensions for: Vertical scrolling content at a width equivalent to 320 CSS pixels". A page-sized PDF on a phone fails that by construction: the reader scrolls both ways, or zooms out until the text is too small.
The DAISY Consortium, writing about fixed-layout publications generally, is blunt about how hard this is to fix: conforming to older WCAG "may be possible", but conforming to current versions "is much more difficult due to the reflow requirement that was added in 2.1."
They name the criteria that break, and each applies to a PDF ebook:
- Reflow, where "the zoom requirement of this success criterion typically results in the user having to scroll both axes to read the content"
- Text Spacing, where "the overflow text is often hidden from sight"
- Images of Text
- Meaningful Sequence, because "content elements can be visually placed wherever needed, care is not always taken to ensure that a logical sequence is maintained in the markup"
Note that none of this is about PDF being a bad format. It is about fixed pages being wrong for reading on an unknown screen. A fixed-layout EPUB has exactly the same problem.
Which Retailers Take Which
The practical constraint, and it settles the question for most people.
| EPUB | ||
|---|---|---|
| Amazon KDP | yes | accepted, nine languages only |
| Apple Books | yes, EPUB 3 only | no |
| Kobo Writing Life | yes | no |
| Google Play Books | yes | yes |
Amazon's restriction is specific: "We only support PDF files in the following languages: English, French, German, Italian, Portuguese, Spanish, Catalan, Galician, and Basque."
Apple takes EPUB only, with PDFs permitted merely as assets embedded inside one. Kobo's accepted formats are ".doc and .docx, .odt, .ePub, .mobi", with PDF absent from every list.
So a PDF-only ebook cannot be sold on two of the four major stores. That alone decides it.
When PDF Is the Right Answer
It genuinely is, in these cases:
The print interior. Non-negotiable. Print on demand platforms take PDF and the page is fixed by definition.
Books where position carries meaning. Cookbooks, illustrated references, poetry with strict visual form, technical books with complex tables. A university press describes offering PDF for readers who "prefer a fixed layout, particularly with textbooks, highly illustrated books, or titles with mathematical formulas."
Direct sales of a designed artefact, such as a workbook, a score or a pattern, where the buyer expects to print it.
Proofs and review copies, where you want everyone looking at the same page.
What these share is that the fixed page is the point, not an accident of production.
What Deckle Exports
Deckle exports both, and the split follows the reasoning above rather than treating them as interchangeable.
PDF is the print path. This is where trim size, margins and gutter, bleed, running headers and page numbers apply, because they are properties of a fixed page. Deckle applies bleed on three edges and enforces the platform gutter minimum for your page count.
EPUB is the ebook path. Reflowable, built to the specification rather than zipped from a folder, with the required metadata and a generated navigation document.
Two things worth knowing if you were considering selling the PDF as your ebook. Deckle's print PDF is laid out for a specific trim size, so on a phone it is a 6 by 9 inch page shown small, with margins and gutter sized for a binding that does not exist. And Deckle's PDF is a standard PDF rather than a tagged PDF/UA file, so it carries no structure tree or alt text, which is the accessibility gap described above.
If you want to distribute a fixed-layout reading edition alongside the ebook, that is a legitimate choice. Use the print PDF for it, sell the EPUB as the ebook, and do not substitute one for the other.
For the three-way comparison including manuscript handoff, see EPUB vs PDF vs DOCX. For what changes between the two outputs, see ebook vs print formatting differences.
Common Mistakes
- Saying PDF is inaccessible. It can be highly accessible. It requires tagging work that a default export skips.
- Selling a print PDF as your ebook. It is laid out for a page that the reader does not have.
- Assuming every store takes PDF. Apple and Kobo do not, and Amazon restricts it to nine languages.
- Choosing PDF to preserve your typography. In a novel that costs the reader font control for no benefit.
- Thinking fixed-layout EPUB solves it. Same reflow failure, different container.
- Offering only a PDF for a text-only book. There is no case for it.
FAQ
Q: Can I sell a PDF as an ebook? A: On Amazon in nine languages and on Google Play. Not on Apple Books or Kobo.
Q: Is PDF really inaccessible? A: No. Tagged PDF and PDF/UA support assistive technology well. A default export is not tagged, which is the actual problem.
Q: Why does everyone say EPUB is more accessible? A: Because its accessibility comes from HTML semantics you write anyway, and because it reflows. PDF's requires a separate pass.
Q: What about poetry, where line breaks matter? A: EPUB handles verse fine with proper markup. Fixed layout is for cases where two-dimensional position carries meaning.
Q: Should I give buyers both? A: For direct sales, offering both is generous and easy since you are producing both anyway.