KDP margin rules
The inside margin (gutter) is the one next to the binding. Thicker books curve more at the spine, so KDP asks for a wider gutter as the page count grows:
KDP Interior Margin Calculator
KDP rejects interiors with text too close to the edge or the binding. Enter your trim and page count to get the minimum margins, the PDF page size to export and the area you can safely fill.
Margin rules from KDP's help pages, checked 2026-11-13.
PDF page size
6 × 9 in
same as the trim size
Inside (gutter) margin
0.375 in
minimum for 120 pages
Top, bottom, outside
0.25 in
minimum without bleed
These are KDP's minimums. Most designers add a little more (for example 0.5 in outside) so nothing feels cramped after trimming.
| Page count | Minimum inside margin |
|---|---|
| 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 top, bottom and outside margins must be at least 0.25 in without bleed and 0.375 in with bleed.
Bleed or no bleed?
Choose bleed only if images or backgrounds touch the edge of the page. Then your PDF must be 0.125 in wider and 0.25 in taller than the trim (a 6 × 9 in book becomes 6.125 × 9.25 in), and KDP trims the extra off. Most novels, journals and line-art coloring books with a white border don't need bleed.
Coloring books: one-sided pages
Coloring pages are usually printed on one side only so markers don't bleed through onto the next design. That doubles the page count (every design is followed by a blank page), which moves you into a wider gutter band and raises the printing cost.
Questions
›What margins does KDP require?
An inside margin from 0.375 in (24 to 150 pages) up to 0.875 in (701 to 828 pages), and at least 0.25 in on the top, bottom and outside, or 0.375 in if your book has bleed.
›What size should my interior PDF be?
The trim size without bleed. With bleed, add 0.125 in to the width and 0.25 in to the height.
›Why did KDP reject my margins?
Usually because text or images sit inside the minimum margin, or because a full-page image doesn't extend into the bleed. Check both in KDP's print previewer before you publish.
Sources (checked 2026-11-13)
- Set Trim Size, Bleed, and Margins: Bleed size, inside (gutter) margins by page count, outside margin minimums.