KDP Formatting Guide: Trim Size, Margins, and Bleed Explained
Formatting is where a lot of first books stall. The writing is done, and then the manuscript hits a wall of trim sizes, margins, gutters, and bleed. None of it is complicated once the terms are clear. Here is a plain-English guide to formatting a print interior for Amazon KDP.
Trim size: the 6 x 9 standard
Trim size is the finished dimensions of your printed page. KDP offers many options, but 6 x 9 inches is the workhorse for a reason:
- It suits most nonfiction, general fiction, and self-help.
- It keeps page counts β and therefore printing costs β reasonable.
- Readers are used to it, so it looks like a "real" book.
You can choose another size, but if you are unsure, 6 x 9 is a safe, professional default. Whatever you pick, decide it before you lay out the interior, because changing trim size later reflows the entire book.
Margins and the gutter
Margins are the empty space around your text. They are not wasted space β they make a page readable and stop text from disappearing into the binding.
- Outer margins (top, bottom, and the outside edge) give the eye room and let readers hold the book without covering text.
- The gutter is the inner margin, next to the spine. It needs to be wider than the outer margins because the binding eats some of that space. The more pages your book has, the more the pages curve into the spine, and the larger the gutter should be.
A book with tight or missing gutter margins looks amateur and can be hard to read near the spine. When in doubt, give the inside edge a little more room.
Bleed
Bleed applies when color or images run all the way to the edge of the page. Because printers cannot cut with perfect precision, any edge-to-edge element must extend slightly past the trim line. After the page is printed and trimmed, the color reaches the true edge with no white sliver.
If your interior is plain text with white margins, you do not need bleed. If you have full-page images or colored backgrounds, you do. Set it up before you export, not after.
How many words fit on a page
A useful rule of thumb for a standard 6 x 9 page with normal margins and a readable body font is roughly 270 words per page. That lets you estimate your printed length: a 60,000-word manuscript lands somewhere around 220 pages, before front and back matter. It is an estimate, not a guarantee β font, size, and spacing all shift it β but it is close enough for planning your spine width and pricing.
Print-ready PDF vs DOCX
KDP accepts two main interior formats, and the choice matters:
- DOCX. Convenient. You upload a Word file and KDP converts it. Fine for straightforward, text-only books, but you hand over control of the final layout, and small things can shift in conversion.
- Print-ready PDF. More control. What you export is what prints β fonts, spacing, images, and right-to-left layouts all locked in place. For anything with images, special layout, or non-Latin scripts, a PDF is the safer choice.
If precision matters to you, export a PDF and review it page by page before uploading.
Front and back matter
A finished book is more than chapters. Standard front and back matter signals quality and helps readers:
Front matter typically includes:
- Title page
- Copyright page
- Table of contents (especially for nonfiction)
- Optional dedication or foreword
Back matter often includes:
- An about-the-author page
- A call to action (a request for a review, a link to your next book)
- Acknowledgements or references
These pages count toward your page total, so include them before you finalize the spine width and price.
Let the tool handle the mechanics
The rules above are learnable, but they are also exactly the kind of fiddly, repeatable work software should do. InkStant AI produces a KDP-ready interior with the correct trim, margins, gutter, and matter β including right-to-left layouts for Arabic β so you can review a clean file instead of building one from scratch. You keep control of the content; the tool keeps the formatting between the lines.
Want a properly formatted interior without wrestling with margins? Start for free and generate a KDP-ready file.