How to format a book for KDP

KDP wants two different files from you, and they have almost nothing in common.

For the ebook, it wants an EPUB: a reflowable file where the reader controls the type size and the text repours to fit whatever screen it is on. For the paperback, it wants a print-ready PDF: a fixed file where every page is exactly the size of the printed page, every typeface is embedded, and nothing moves.

Most of the mistakes authors make at upload come from treating those as one job. This is how to do each of them properly.

The Ebook File

Upload an EPUB. KDP will also accept DOCX and a few other formats and convert them for you, but the conversion is a black box, and what you see in the previewer is the result of decisions you did not make. An EPUB you built is a file you can inspect and correct.

Reflowable is what you want for a novel, a memoir, or any book that is mostly running text. The reader changes the font, the size, the margins and the background, and your layout adapts. You do not control line breaks and you should not try to.

Fixed layout is for books where the position of things on the page carries meaning: picture books, comics and graphic novels, some cookbooks, anything with text wrapped around images in a specific arrangement. Fixed layout files are much larger, they do not resize gracefully on a phone, and they are not eligible for some Kindle features. Use it only when reflowable genuinely cannot express the book.

Two ebook-specific rules that catch people out. First, an ebook needs a working navigational table of contents, and it needs to be a real NCX or nav document rather than a page of text you typed. Second, keep the front matter short: Kindle's sample shows the opening portion of the file, and if that portion is a half title, a title page, a copyright page, a dedication, an epigraph and a five-screen table of contents, the sample ends before the story starts.

The Paperback File

Upload a print-ready PDF. It has to satisfy four things at once.

Every typeface embedded. If a font is not embedded, the printer substitutes something and your book comes back set in a face you did not choose. You can check this yourself: open the PDF, look at the document properties, and confirm every font in the list is marked as embedded or a subset. Word on macOS in particular does not always embed fonts when saving a PDF, so verify rather than assume.

Correct trim size. The PDF page size must equal the trim size you selected in KDP. Not Letter, not A4, not the trim size scaled to fit. If your PDF pages are 8.5 by 11 inches and you told KDP the book is 6 by 9, the upload either fails or produces something no one wants.

Bleed handled correctly. If any element touches the edge of the page, such as a full-page image or a decorative band, you need bleed: the page is built 0.125 inches larger on the top, bottom and outside edge, the art extends into that area, and the printer trims it off. If nothing touches the edge, do not use bleed. Adding it unnecessarily just shifts your text block.

Margins that respect the binding. This is the one that ruins otherwise good interiors, and it needs its own section.

Trim Size, and the Gutter that Follows from it

Pick the trim size first, because everything downstream depends on it.

For fiction, the sizes readers expect are 5 by 8, 5.25 by 8, 5.5 by 8.5 and 6 by 9. The smaller sizes read as mass-market and produce more pages; 6 by 9 reads as trade paperback and produces fewer. Nonfiction leans toward 6 by 9 and larger. Look at the shelf your book will sit on, physically or on a retailer page, and match it.

Now the gutter. The inside margin of a printed book has to be wider than the outside margin, because the binding eats part of it, and how much it eats depends on how thick the book is. KDP sets minimums by page count:

• 24 to 150 pages: 0.375 inches
• 151 to 300 pages: 0.5 inches
• 301 to 500 pages: 0.625 inches
• 501 to 700 pages: 0.75 inches
• 701 pages and up: 0.875 inches

Outside, top and bottom margins have a minimum of 0.25 inches without bleed, and 0.375 inches with bleed.

Those are minimums, and a book set at exactly the minimum looks cramped. Add a little.

The part people miss is the loop. Your trim size and type size determine your page count. Your page count determines your minimum gutter. Your gutter changes the width of the text block, which changes the page count again. If you set the interior at 290 pages with a 0.5 inch gutter and revision pushes you to 310, you are now below the minimum and the file will be rejected or printed with text running into the spine. Check the page count against the table after every substantive revision, not just at the start.

KDP also caps total page count, and the cap depends on paper stock and ink; 828 pages is the top end for black ink on white paper and color interiors allow fewer. Check the current limit for the paper you chose before you commit to a trim size that inflates your page count.

This is one of the places where formatting inside your writing tool genuinely helps. Calamus's Compile renders print PDF at real trim sizes from the manuscript you drafted, so the trim size and gutter are settings on the book, and regenerating after a revision recalculates the layout instead of asking you to rebuild it.

Front and back matter, in order

Print convention runs roughly like this, with recto meaning a right-hand page:

1. Half title (recto)
2. Title page (recto)
3. Copyright page (verso, the back of the title page)
4. Dedication (recto)
5. Epigraph, if you have one
6. Table of contents, if the book needs one
7. Prologue or chapter one

Back matter runs: epilogue, author's note, acknowledgments, about the author, also-by list, and then whatever you want readers to do next.

Two adjustments for the ebook. Move the also-by list and any newsletter invitation to the back, where a reader who finished the book will see them. And trim the front matter down, for the sampling reason above; many ebooks open on a short title page and go straight into chapter one, with the copyright page moved to the back.

Why Word's Default Styles Cause Trouble

Word can produce an acceptable file, but not with the settings it ships with.

The Normal style is set for a Letter page with 1 inch margins and no gutter, which is wrong for every trim size on the list. Chapter headings applied with the font size dropdown rather than a named style give the converter nothing to build a table of contents from. First-line indents typed as tabs or spaces survive into the EPUB as literal characters and look wrong at every font size. Automatic hyphenation, widow and orphan control, and the space between a chapter number and its title are all handled by direct formatting that has to be reapplied by hand every time you touch the document.

If you do use Word, use real named styles for every element, set the page size to your trim size, set mirrored margins with a proper gutter, and check font embedding on export. That is most of the work a formatter would have done for you.

Checking the Result

Do all four of these before you hit publish.

Run the ebook through Kindle Previewer, on a phone-sized device and a tablet-sized one, at the smallest and largest font settings. Broken layouts show up at the extremes.

Validate the EPUB. EPUBCheck reports structural errors that a previewer will silently render around and a retailer other than Amazon may reject.

Use KDP's print previewer and turn on the page-boundary view, which shows you where the trim line falls. Look at a spread near the middle of the book, where the gutter is under the most pressure.

Then order a proof copy. Nothing on a screen tells you whether the inside margin is wide enough to read comfortably, whether the type is too small for the trim size, or whether the paper stock you picked shows the ink through. It takes about a week and it is the only step that catches the physical problems.

If you want the drafting and the formatting to live in the same project so that this checklist does not restart after every revision, that is what Calamus is built around, and there is a 14-day trial if you want to see the outputs before deciding.