How print and eBook files differ by design
A print file is fixed. Every page has a trim, margins, a gutter, and a text block that does not move. The file you upload for print is a PDF at 300 dots per inch with bleed, and the printer reproduces that PDF exactly as laid out. A one-point change in leading moves text by one point on the page, and the pagination changes only when you add or remove pages.
An eBook file is reflowable. The text reflows to the device size, the typeface the reader chooses, and the font size the reader sets. The file you upload for eBook is an EPUB — a zip of XHTML and CSS — that describes the text and its hierarchy, not its position. A one-point change in leading in the source file changes the CSS, but the device may still reflow the text to its own line length. Pagination does not exist until the device renders.
The tool starts from where the book will sell, because the retailer determines which file type it will accept and how it will handle it. KDP Print takes only print PDF. KDP eBook takes EPUB or its own KPF. Apple Books, Kobo, and Google Play take EPUB. IngramSpark takes print PDF for print and EPUB for eBook. The same book that is print plus eBook on KDP needs two files; the same book that is wide eBook on three retailers needs one EPUB that passes all three. The distribution you pick is the file decision, not the file extension.
Fixed-layout is the third type, for art-heavy books where reflow would break the design. A fixed-layout EPUB preserves the exact position of text and images, like a PDF, but inside the EPUB container. Children picture books, cookbooks, and heavily illustrated books where the art must not move need fixed-layout. Text-heavy books need reflowable, because reflowable is more accessible, more widely supported, and more forgiving on small screens. The tool asks whether the book has fixed layout so it can recommend the correct EPUB type.
The EPUB package contract
An EPUB is not a file. It is a contract between your source and the retailer's pipeline, and the contract is enforced by validation.
Inside, an EPUB is a zip that contains XHTML files for the text, a CSS file for the style, image files, a manifest that lists every file, a spine that orders the reading sequence, and a metadata file that names the title, author, and cover. The retailer unzips that contract, checks that every file the manifest lists is present, checks that every file the spine orders is in the manifest, checks that the cover image is the one the metadata names, and then re-encodes the whole thing for its store. A missing file, a misnamed cover, or a broken link will fail validation before any human sees the book, even though the text is correct. The tool does not validate the package, but it tells you which package each retailer expects so the file you build will be the one the contract describes.
Reflowable status is part of that contract. A reflowable EPUB declares that the text may reflow, and the retailer will display it with the reader's font choice. A fixed-layout EPUB declares exact pages and positions, and the retailer will display it as the designer laid it out. The declaration lives in the EPUB's metadata and in the CSS. A reflowable file that contains fixed-layout pages will be rendered as reflowable and the fixed pages will break; a fixed-layout file that contains reflowable text will be rendered as fixed and the text will not reflow. Choose the declaration that matches the book, not the file extension.
Why the print PDF is not an EPUB with a different extension
A print PDF and an EPUB can be built from the same source file, but they are not the same file at different sizes. The print PDF embeds the fonts at the size and leading chosen for the trim, with the text placed at the exact x and y coordinates inside the text block, with the cover as a separate spread that includes spine and bleed. The EPUB embeds the text as reflowable XHTML with CSS that describes headings, paragraphs, and lists, with images referenced inline and the cover as an image resource. The PDF knows where the text is; the EPUB knows what the text is.
A PDF renamed to .epub will not reflow because it has no reflowable structure, only positioned glyphs. An EPUB renamed to .pdf will not have the print margins, bleed, or 300 DPI image resolution that print requires, because it was built to reflow. The two files share the words, but they do not share the layout contract, and the retailer will enforce the contract it expects. The print pipeline checks for bleed and embedded fonts; the eBook pipeline checks for reflowable structure and cover image metadata. A file that passes one will fail the other, even when the text is identical.
What each retailer actually takes
KDP Print takes only PDF. The PDF must be at 300 dots per inch, with bleed, with fonts embedded, and with the cover as a separate spread. KDP will not accept an EPUB for print, and a Word file uploaded for print will be converted to PDF with less predictable pagination. The print PDF is the master for paperback and hardcover. Keep it as a layered PDF from the source file, not as a conversion from the EPUB.
KDP eBook takes EPUB or KPF. KPF is KDP's own package built from Kindle Create or the KDP previewer, but EPUB is the portable master that also passes the wide retailers. For KDP Print plus eBook, upload two files: the print PDF for the paperback and the EPUB or KPF for Kindle. Do not upload the print PDF as the eBook. A print PDF uploaded as an eBook will not reflow and will be rejected or will look broken on small screens, because the PDF's fixed pages cannot adapt to the device.
Wide eBook on Apple Books, Kobo, and Google Play takes one EPUB. Apple requires EPUB in sRGB with a cover at 1400 by 2100 minimum, Kobo at 1600 by 2400, Google at 1600 by 2400 as well, all under their file caps. One reflowable EPUB at 1600 by 2400 cover and with reflowable text will pass all three, plus KDP eBook, if it is valid EPUB 3 and the cover is inside the EPUB package. The same fixed-layout EPUB will also pass all three, but it should only be used when the art must not reflow. The tool does not create separate files per retailer for reflowable; it creates one.
IngramSpark takes a print PDF for print and an EPUB for eBook, like KDP. For wide print plus eBook, you need two masters: the print PDF for the paperback or hardcover that IngramSpark will print, and the reflowable EPUB for the eBook retailers. The print PDF for IngramSpark and the print PDF for KDP can be the same file if the trim, paper, and cover match, but the distribution record is separate.
Print-only and eBook-only are also valid distributions. A print-only book, such as a workbook that is not meant to be read on a phone, needs only the print PDF. An eBook-only book, such as a lead magnet, needs only the reflowable EPUB. The tool reflects those cases by returning a single file. The primary call to action for a print-only book is not an eBook preview, and the file decision reflects that.
Reflowable versus fixed-layout and when to choose which
Reflowable EPUB is a web page in a book container. The text is described as headings, paragraphs, lists, and figures, and the device lays it out. The reader can change font, size, and line spacing, and the book reflows. The file is accessible, lightweight, and widely supported. It is the correct choice for text-heavy books, which is most books.
Fixed-layout EPUB is a set of page images with text and art locked in place. The text does not reflow. The reader cannot change the font without breaking the design. The file is larger, less accessible, and supported only on devices that handle fixed-layout. It is the correct choice for art-heavy books where the position of the art relative to the text is part of the meaning: children picture books where the illustration must stay with the words, cookbooks where the photograph must stay with the recipe, and heavily illustrated books where the art would be orphaned if it reflowed.
The decision is not about quality. Reflowable is not a lesser file; it is the file that respects the reader's control over the reading experience. Fixed-layout is not a premium file; it is the file that preserves a design that depends on position. Choose reflowable unless the art must not move, then choose fixed-layout.
The tool adds a warning when fixed-layout is selected for wide eBook, because the distribution is correct but the tradeoffs are real. Fixed-layout is less accessible, larger, and more likely to be rejected for a text-he way book that could have been reflowable. The warning is not a failure; it is a prompt to confirm that the art must not reflow before committing to the format that locks it.
Worked examples with the file per retailer shown
Note: the following examples are hypothetical and illustrative rather than a sourced case study.
KDP Print plus eBook with a reflowable text-heavy book is the common case. Distribution KDP Print plus eBook, fixed layout false, illustrations false. The tool returns Use PDF for print plus EPUB or KPF for eBook, with KDP Print taking print PDF and KDP eBook taking reflowable EPUB or KPF, Apple, Kobo, and Google taking reflowable EPUB, and Illustrations as inline in EPUB. The breakdown shows KDP Print and IngramSpark as print PDF, KDP eBook, Apple, Kobo, Google, and IngramSpark eBook as reflowable EPUB. The metrics show distribution KDP Print plus eBook, file to upload PDF for print plus EPUB or KPF for eBook, retailers Amazon KDP, and art-heavy no. The recommendations say reflowable is correct for text-heavy books, to upload two files for KDP, and to keep print and eBook as separate masters from the source file.
Wide eBook with a fixed-layout art-heavy book is the art-heavy case. Distribution wide eBook, fixed layout true, illustrations true. The tool returns Use fixed-layout EPUB, with Findaway and all wide eBook retailers taking fixed-layout EPUB, plus the print PDF if print is also distributed, and Illustrations as fixed in place. The metrics show distribution wide eBook, file to upload fixed-layout EPUB, retailers Apple, Kobo, Google, and KDP eBook, and art-heavy yes. The breakdown shows KDP eBook, Apple, Kobo, Google, and IngramSpark eBook as fixed-layout EPUB. The recommendations say fixed-layout is for art-heavy books only and to confirm the art must not reflow, and that the EPUB should be tested in each retailer's previewer because they re-encode differently.
Print-only is the third. Distribution print only, fixed layout false, illustrations false. The tool returns Use print PDF only, with KDP Print and IngramSpark as print PDF and no eBook file. The breakdown shows only KDP Print and IngramSpark as print PDF. The metrics show file to upload print PDF and art-heavy no. The recommendations say print-only has no eBook preview, so the primary call to action is not a next-book preview, and the file is the print master.
Edge cases: Word files, KPF, and the single-file temptation
Word files test the temptation to upload one file everywhere. KDP will accept a Word file for eBook and convert it to KPF, and it will accept a Word file for print and convert it to PDF, but the conversions are less predictable than an EPUB and a PDF you exported from the source file. A Word file with mirrored margins and reflowable images may convert to an EPUB that looks correct, but a Word file with manual line breaks, text boxes, and floating images may convert to an EPUB where the images are misplaced and the headings are not hierarchical. Export reflowable EPUB from the source file for the best control, and export print PDF from the same source with the print settings.
KPF is KDP's own eBook package. It is built from Kindle Create or from the KDP previewer's conversion of an EPUB. For KDP eBook, KPF and EPUB both pass, and KPF can be convenient when the interior was built in Kindle Create. For wide eBook, KPF does not pass; wide retailers take only EPUB. If you publish KDP plus wide, keep the EPUB as the master and let KDP create the KPF from it, rather than maintaining a KPF that cannot be reused wide.
Single-file temptation is the wish to export one EPUB and convert it to PDF by changing the extension, or to export one PDF and use it as the EPUB. Both fail. An EPUB converted to PDF by renaming will not have the print margins, gutter, bleed, or the 300 DPI image resolution that print requires. A print PDF used as an eBook will not reflow and will be rejected or will look broken on small screens. Keep two masters, print PDF and reflowable EPUB, exported from the same source file with the correct settings for each. The source file is the single source; the two exports are the two products.
Illustrations test the reflow decision. A book with five or more illustrations, tables, or figures should include a list of illustrations in the front matter if the book is nonfiction, and each image should have alt text for accessibility in the EPUB. For reflowable EPUB, the images are inline and will reflow with the text. For fixed-layout, the images are fixed in place. The tool flags illustrations as inline in reflowable and fixed in place in fixed-layout, so you can see the consequence of the format choice without opening the file.
How to use the tool in under two minutes
Pick where the book will sell. KDP Print plus eBook, wide eBook on Apple, Kobo, and Google, print only, eBook only, or wide print plus eBook everywhere. The distribution you pick is the file decision, not the file extension. Each choice maps to a file set: print PDF, reflowable EPUB, fixed-layout EPUB, or the combination.
Mark whether the book is art-heavy or fixed-layout and whether it has five or more illustrations. Art-heavy means the art must not reflow; illustrations means the eBook needs inline images with alt text and, for nonfiction, a list of illustrations. The tool uses those two booleans to choose between reflowable and fixed-layout for the eBook and to add the illustration note.
Read the file to upload per retailer. Print always needs PDF, eBook needs EPUB or fixed-layout EPUB, and wide needs the same EPUB everywhere. The breakdown lists each retailer with the file and the note, so you can see that a single EPUB passes Apple, Kobo, Google, and KDP eBook, while print needs its own PDF.
Check the recommendations. Reflowable is correct for text-heavy books; fixed-layout is for art-heavy only. For KDP Print plus eBook, upload two files, not one. For wide, one EPUB passes all, but test the EPUB in each retailer previewer. Keep print and eBook as separate masters from the source file.
Common mistakes and how to avoid them
Uploading a PDF as an eBook is the most common. Print needs PDF because print is fixed on paper. eBook needs EPUB because eBook reflows. A PDF uploaded as an eBook will not reflow and will be rejected or will look broken on small screens. Upload the correct file per retailer, not the same file everywhere.
Choosing fixed-layout for a text-heavy book because it looks more precise is the second. Fixed-layout preserves the exact position of text and images, which is the right choice for art-heavy books where the art must not move. For text-heavy books, fixed-layout is less accessible, larger, and more likely to be rejected for a book that could have been reflowable.
Converting a print PDF to EPUB by changing the extension is the third. An EPUB is not a renamed PDF; it is a zip of reflowable XHTML and CSS. A print PDF converted to EPUB by renaming will not reflow and will not pass validation. Export reflowable EPUB from the source file with the correct settings.
Forgetting the list of illustrations is the fourth. A nonfiction book with five or more figures should include a list of illustrations in the front matter, on a right-hand page after the table of contents. The tool flags illustrations as inline in reflowable and reminds you to include the list when appropriate.
Leaving the cover out of the EPUB is the fifth. The EPUB's cover image inside the package should be the same portrait eBook cover at the recommended pixels, not the print spread. The print wrap includes spine and bleed; the eBook cover is the front panel only.
Expecting KDP to fix widows automatically is the sixth, for the interior, but the file decision matters for the same reason. KDP prints what you upload for print and displays what you upload for eBook, without reflowing a PDF into an EPUB. You must fix the text and re-export the correct file type.
Final checks before you commit and upload
Run the tool once with the distribution you actually publish to and once with a second distribution that is one step away — for example, KDP Print plus eBook and wide eBook, or wide eBook and wide print plus eBook. The file sets should differ by one file: print PDF appears or disappears, and the EPUB stays the same. If the same file would allegedly serve both, the file is likely the wrong type for one of them.
Open the exported print PDF at 100% and check the spread: trim, gutter, outside, top, bottom, and the text block. Open the exported EPUB in a validator or in the Kindle Previewer and check the reflow: headings, paragraphs, lists, and figures should reflow to the window size. The print PDF should not reflow, and the EPUB should. The two files should look different at the same window size, which is the proof that they are correct for their medium.
Compare the cover files. The print wrap should be back plus spine plus front plus bleed, the eBook cover should be the front panel only at the portrait ratio, and the audio cover should be the square. The print PDF, the eBook EPUB, and the audio cover are three objects, not one file at three sizes. The tool lists the file per retailer so you can see which object goes where, but the objects themselves must be built as separate masters.
Upload and verify live. In the KDP and IngramSpark previewers, check that the print PDF's interior and cover match the expected trim and that the eBook EPUB's reflow is correct on small screens. On the retailer's product page, confirm the eBook cover fills the frame without bars and that the print cover's spine matches pages times PPI. If they do, lock the two masters — print PDF and reflowable EPUB — alongside the KDP file names. When the next book grows, reuse the same export settings rather than relying on memory that the last eBook was EPUB. The settings are the variable that compounds; the content is the variable that varies.