Print Book Formatting: From Manuscript to Paperback
A print book is a physical object. Readers hold it, flip through it, notice the margins. Here's how to get them right.
The Six Pillars of Print Formatting
Trim sizes (the standard options and what they signal)
Trim size is the finished physical dimensions of your book. The most common fiction trim size is 6" x 9", which reads as a standard trade paperback. Mass-market paperbacks use 4.25" x 6.87" — a smaller, denser format associated with genre fiction sold in airports and supermarkets. For literary fiction, essays, and non-fiction, 5.5" x 8.5" is also widely used.
Your trim size choice signals genre. Romance and thriller readers associate 5.5" x 8.5" or 5.06" x 7.81" with the category feel they expect. Pick a size that matches your genre's conventions, then check KDP Print's paper availability for that trim — not every size is available in every paper type. Your trim size also drives page count, which affects spine width, which affects whether your title fits on the spine.
Margins and bleed (what the printer needs)
Print margins are larger than they look on screen. A standard interior requires outside margins of at least 0.5" and inside (gutter) margins that scale with page count: 0.375" for under 150 pages, up to 0.875" for books over 600 pages. KDP Print publishes a margin table — use it. Tight gutters cause text to disappear into the spine.
Bleed applies to the cover, not the interior. If your cover background extends to the edge of the page, you need a 0.125" bleed on all sides so the printer has material to trim. Interior images that go to the page edge also need bleed. For a standard text-only interior, bleed is not required. Set your interior document to the exact trim size with no bleed unless you're running full-page images. Export as PDF/X-1a for best print compatibility.
Fonts for print (readability at 10-11pt)
Print fonts behave differently from screen fonts. Serifs — the small strokes at the ends of letterforms — significantly improve readability in print at body text sizes. Garamond, Caslon, Palatino, and Minion Pro are industry standards for book interiors. Georgia and Times New Roman work but read slightly more functional than literary.
Body text for a 6" x 9" trade paperback typically sits at 10.5pt to 11pt with 14pt leading (line spacing). A smaller trim size can drop to 10pt. Never go below 10pt for body text — it strains eyes. Chapter headings can use a display font or a weight variation of your body font. Avoid body fonts that are purely display or decorative. Consistency matters: use the same font family throughout, varying only weight and size for hierarchy.
Headers, footers, and page numbers
Running headers and page numbers make a print book feel professionally published. Standard practice: odd (right-hand) pages carry the chapter title or book title in the header; even (left-hand) pages carry the author name. Page numbers sit at the outside bottom corner or centered in the footer.
Front matter — title page, copyright, dedication, table of contents — uses lowercase Roman numerals (i, ii, iii) or no numbers at all. Chapter one begins on a right-hand page, numbered from page 1. First pages of chapters typically suppress the running header. Set all of this via section breaks and linked/unlinked header-footer sections in Word, or automatically in Vellum and Atticus. Headers should use a smaller point size than body text (8-9pt) and are often set in small caps or a lighter weight to distinguish them from the reading text.
Cover file requirements for KDP Print and IngramSpark
Your print cover must be a single flat PDF that includes front cover, spine, and back cover in one file. The spine width depends on your page count and paper type — KDP and IngramSpark both provide spine width calculators. A 300-page book on white paper has a different spine than the same book on cream paper.
Resolution must be 300 DPI minimum — anything lower prints visibly pixelated. Color mode should be CMYK, not RGB; screen colors and print colors differ, and RGB files submitted to printers shift unpredictably. KDP Print accepts RGB and converts it, but the results are less accurate. Embed all fonts in the PDF. Check the final cover file in a PDF viewer that shows actual dimensions before uploading. IngramSpark is stricter about technical specifications than KDP — if you plan to use both, design to IngramSpark's spec.
Exporting your print-ready PDF
The final step is exporting a PDF that the printer can use. In Word, export via "Save As PDF" with the "Best for printing" option — not "Best for online publishing." In Vellum, Atticus, or InDesign, use the built-in PDF export with print settings. The correct PDF standard for print is PDF/X-1a (older, universally supported) or PDF/X-4 (supports transparency and color profiles).
Flatten all transparency before export. Embed all fonts. Set color profile to the printer's specification — KDP Print uses sRGB for covers and accepts standard settings for interiors. Check your exported PDF by opening it in Adobe Acrobat Reader and zooming to 100% on a chapter opening page, a mid-book spread, and your last page. Verify margins, headers, and that no text touches the trim edge. Then order a physical proof copy before approving your book for sale.
Frequently Asked Questions
How do I choose the right trim size for my novel?
Start with genre conventions. Trade fiction typically uses 5.5" x 8.5" or 6" x 9". Look at comparable books in your genre on Amazon — the product page lists trim size under 'Book details'. If you're writing literary fiction, 5.5" x 8.5" is the most common. For thrillers and genre fiction going wide, 6" x 9" is safe. Avoid unusual trim sizes unless you have a specific design reason — they limit paper options and can look odd in readers' hands. Your trim size determines your page count and spine width, so finalize it before designing your cover.
What margins does KDP Print require?
KDP Print requires minimum outside margins of 0.25" and inside (gutter) margins that scale with page count. For 24-150 pages: 0.375" gutter. For 151-300 pages: 0.5". For 301-500 pages: 0.625". For 501-700 pages: 0.75". For 701-828 pages: 0.875". These are minimums — most designers use slightly larger gutters for comfortable reading. KDP also recommends top and bottom margins of at least 0.5". Always check KDP's current guidelines before finalizing, as they update them periodically.
How do I calculate spine width?
Spine width depends on page count and paper type. KDP and IngramSpark both provide spine width calculators on their sites — input your page count and paper choice (white or cream) and get the exact measurement. As a rough guide, white paper is slightly thinner per page than cream, so the same page count produces a narrower spine. You need this number before finalizing your cover file. A spine that's too narrow for your title means your title won't fit; always allow a small safety margin and verify with a proof copy.
Where does the ISBN go on a print book?
The ISBN barcode goes on the back cover, typically in the lower-right corner. It should be at least 1.5" wide and printed in black on a white or light background for reliable scanner reads. If your cover design has a dark background, add a white box behind the barcode. The ISBN number itself should also appear on the copyright page inside the book. If you're using a KDP-assigned free ISBN, KDP places the barcode on the back cover automatically if you let them — but you lose flexibility in where it appears, which can interfere with back cover design.
What's the difference between KDP Print and IngramSpark for print formatting?
The core formatting requirements are similar, but IngramSpark is stricter about file specifications and has less tolerance for errors. IngramSpark charges a setup fee (currently $49) and a revision fee if you update files after publication. KDP Print is free to set up and revise. IngramSpark offers broader distribution to bookstores and libraries; KDP Print's expanded distribution is more limited. Many authors publish on both: KDP Print for Amazon sales, IngramSpark for bookstore and library distribution. If you do, format to IngramSpark's stricter spec — a file that passes IngramSpark's checks will always pass KDP's.