KDP margin calculator
The inside margin grows with page count: a thicker book loses more of the inner edge into the binding. These are minimums — going under them is one of the most common reasons an interior is rejected.
Showing a paperback, 6" x 9", 120 pages.
- Inside (gutter) margin
- 0.375 inRequired at 120 pages
- Outside, no bleed
- 0.250 inTop, bottom and outer edge
- Outside, with bleed
- 0.375 inMeasured from the trim edge, not the bleed edge
Why bleed changes the outside margin
A bleed interior is printed oversized and cut down, and the cut has a tolerance. KDP therefore asks for 0.375 in of clearance rather than the 0.25 in a non-bleed interior needs, so a trimmer running a little wide does not take your text with it.
The gutter is not the same on both pages
The inside margin is on the left of a right-hand page and on the right of a left-hand page. A document with one fixed left margin has the gutter on the wrong side of every second page — which the pre-flight check will report, and the printer will not.
Check a finished PDF against these margins — it measures where the text actually sits, page by page.
The rules behind these numbers
- Text runs into the margins or the binding
Content must stay 0.25" from the trim edge on a page without bleed, 0.375" on one with it, and clear of the inside margin, which grows with page count.
- Bleed and where it applies
Bleed adds 0.125" beyond the trim so ink runs off the cut edge, and applies to outer edges only.