By Jesse Wood, founder of Build Until Publishing · November 10, 2026 · 6 min read
KDP paperback formatting comes down to three choices: a trim size (6 x 9 inches is the standard for nonfiction), an inside margin that grows with your page count (at least 0.375 inches for short books), and bleed only if images reach the page edge. Then export one PDF with every font embedded.
Formatting is where most first-time authors get rejected or end up with words disappearing into the spine. The rules are simple once you see them in one place.
Most nonfiction authors choose 6 x 9 inches. Trim size is the finished page size after printing. A bigger page holds more words, but it also costs more to print and changes your spine and cover math.
Here's the easiest way to decide. Pull three bestselling books like yours off your shelf, or look at them on Amazon, and match the shape your readers already expect. Not sure how to find those books? Our post on comp titles walks through it.
Your inside margin, called the gutter, has to grow as your page count grows, from 0.375 inches up to 0.875. A thick book bends more at the spine, so you need extra room or the words get swallowed. KDP sets the minimums:
| Page count | Inside margin, at least |
|---|---|
| 24 to 150 | 0.375 in |
| 151 to 300 | 0.5 in |
| 301 to 500 | 0.625 in |
| 501 to 700 | 0.75 in |
| 701 to 828 | 0.875 in |
The outside, top and bottom margins must be at least 0.25 inches with no bleed, and 0.375 inches with bleed. Those are the floors, not the goal. A page with margins of 0.6 inches or more looks calmer and reads better. It also protects you if the trimming shifts a hair.
These numbers apply to paperbacks and hardcovers. Confirm them against KDP's own help pages before you finalize, since Amazon can update its specs.
Only if images or colors run to the edge of the page. Bleed means an image or color runs all the way off the edge of the page. Printers can't print right to the edge, so they print a little extra and trim it off.
You'll choose bleed or no bleed in KDP's print options, so make the decision before you build your file. The book specs calculator shows your exact PDF page size both ways.
Build one clean PDF and check these points.
Paperbacks run from 24 to 828 pages depending on ink and paper. Hardcovers run 75 to 550 pages.
No. Don't try to use the print PDF for Kindle. The ebook is a different file: an EPUB or a Word document (DOCX). Amazon's free Kindle Create turns a Word file into a clean ebook. Use real heading styles for your chapter titles so the table of contents works on every device.
Run KDP's Print Previewer and order a printed proof. When you upload your interior to KDP, run the Print Previewer and fix every flag it raises. Then order a printed proof. Check that nothing sits too close to the inside edge, the page numbers are in the right place, and the chapters begin where you expect.
A few quick checks before you upload:
Each one is easy to fix before you upload and annoying to fix after you've ordered a proof. Run through the list once more before you click Save.
The cover comes next, and its size depends on your trim size, page count and paper color, so lock the interior first. Once your page count is final, use our guide to calculating cover size and spine width. If you change the page count later, the spine changes too.
Want a checklist that tracks your files from here to launch? Start free and you'll get your own publishing checklist page, your Voice profile and the Acquisitions Board's read on your idea.
For business and other nonfiction, 6 x 9 inches is the standard. Memoir and fiction often use 5.5 x 8.5 or 5 x 8 inches. Look at comparable books and match them.
It depends on your page count. Books of 24 to 150 pages need at least 0.375 inches, and books of 151 to 300 pages need at least 0.5 inches. Thicker books need more, up to 0.875 inches.
Only if images or colors run to the edge of the page. If you use bleed, add 0.125 inches to the top, bottom and outside edge. Text-only books don't need it.
One PDF with every font embedded, images at 300 DPI and a page size matching your trim size. The cover goes in a separate PDF.