KDP margin & gutter calculator
Find KDP's minimum inside (gutter) and outside margins for your page count, the PDF size you need with or without bleed, and the margins published novels actually use.
| KDP minimum | Comfortable for reading | |
|---|---|---|
| Inside (gutter) | ||
| Outside | 0.625″ | |
| Top | 0.75″ | |
| Bottom | 0.75″ |
Why the gutter grows with your page count
The thicker the book, the more of each page curves into the binding. KDP sets a minimum inside margin (the gutter) by page count, so text doesn't disappear into the spine:
| Page count | Minimum inside margin |
|---|---|
| 24 to 150 | 0.375″ (9.6 mm) |
| 151 to 300 | 0.5″ (12.7 mm) |
| 301 to 500 | 0.625″ (15.9 mm) |
| 501 to 700 | 0.75″ (19.1 mm) |
| 701 to 828 | 0.875″ (22.3 mm) |
Outside margins and bleed
The outside, top and bottom margins must be at least 0.25″ (6.4 mm) without bleed, or 0.375″ (9.6 mm) with bleed. If your interior has bleed, make the PDF 0.125″ wider and 0.25″ taller than the trim size, so art can run past the edge that gets trimmed.
Minimum isn't the same as good
KDP's numbers are the least it will print. Most published novels use more: around 0.625″ outside and 0.75″ top and bottom, with an extra 0.125″ on the gutter so the text sits comfortably in the open book. That's what the “comfortable” column shows, and what Pressetter uses by default.
Numbers checked against KDP's help page “Set trim size, bleed, and margins” on November 13, 2026.
Writing in Google Docs?
Pressetter typesets your Google Doc into a KDP-ready paperback PDF and a Kindle eBook, then tells you your exact page count, spine width and cover size. The check and a full watermarked preview are free.
Questions
What margins does KDP require for a 6×9 book?
It depends on the page count, not the trim size. For 151 to 300 pages, KDP's minimum inside (gutter) margin is 0.5″ and the outside, top and bottom are at least 0.25″ (0.375″ with bleed).
What is the gutter margin?
The gutter is the inside margin, next to the binding. KDP requires a bigger gutter for thicker books, from 0.375″ under 150 pages up to 0.875″ over 700 pages.
Do I need bleed?
Only if images, color or backgrounds run to the edge of the page. Most novels don't need bleed. If you use it, your PDF must be 0.125″ wider and 0.25″ taller than the trim size.