KDP margin rejections are the single most common reason PDFs fail file review — roughly 40% of all interior rejections are margin-related. The error appears as “your interior file does not meet our requirements” without specifying which margin failed. The most frequent cause: your inside (gutter) margin is too narrow for your page count. A 300-page book requires 0.5” minimum gutter, but if your back matter pushed it to 305 pages, you now need 0.625” — and KDP doesn’t warn you about the boundary.

KDP’s margin requirements

Inside (gutter) margin — the one that causes problems

Page CountMinimum Inside Margin
24–150 pages0.375”
151–300 pages0.5”
301–500 pages0.625”
501–700 pages0.75”
701–828 pages0.875”

Source: KDP content guidelines

Outside margins (top, bottom, outside edge)

  • Without bleed: 0.25” minimum on all three edges
  • With bleed: 0.375” minimum on the outside edge; 0.25” on top and bottom

The page count trap

This catches more authors than any other margin issue. Here’s what happens:

  1. Your manuscript formats to 298 pages → 0.5” gutter is fine
  2. You add an “About the Author” page and a “Also By” page → now 302 pages
  3. The minimum gutter jumps from 0.5” to 0.625” → your 0.5” gutter is now rejected
  4. KDP says “file does not meet requirements” without mentioning the 4-page difference

The fix: Always check your final PDF page count — not your manuscript page count — against the gutter table. If you’re within 10 pages of a boundary (150, 300, 500, 700), either add/remove a page to stay in the current tier, or increase your gutter to meet the next tier.

Use the KDP Book Calculator — enter your word count and trim size, and it shows exactly which margin tier you fall into.

How to measure your current margins

In Adobe Acrobat

  1. Tools → Measure → Measuring tool
  2. Click from the page edge to where your text starts
  3. Check the inside margin on both left and right pages (they alternate gutter side)

In any PDF viewer

  1. Check your page size against your trim size (they should match)
  2. Look at the document properties for page dimensions
  3. Subtract the text block width from the page width, divide by 2 for a rough margin estimate

In your formatting tool

Check your page setup / layout settings for:

  • Inside/gutter margin value
  • Mirror margins should be enabled (left and right pages have different gutter sides)
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Don’t aim for the minimum — aim for professional. These values exceed KDP’s minimums at every page count tier:

EdgeRecommendedKDP Minimum
Inside (gutter)0.75”–0.9”0.375”–0.875” (varies)
Outside0.5”–0.65”0.25”
Top0.6”–0.75”0.25”
Bottom0.7”–0.85”0.25”

With 0.75” gutter, your book passes file review up to 500 pages without any gutter adjustment. That covers the vast majority of fiction and nonfiction.

For a deeper dive on margin theory and readability, see the complete guide to book margins and gutter.

Content bleeding into margins

The other margin error: KDP detects text, images, or page numbers that extend into the margin zone. Common causes:

  • Running headers too close to the edge — headers should respect the top margin
  • Page numbers in the gutter — page numbers must be outside the minimum margin area
  • Indented text extending too far — long block quotes or code blocks might push into the outside margin
  • Images without proper margins — images should have the same margin clearance as text

Quick fix checklist

  • Check your final PDF page count (not manuscript pages)
  • Look up the minimum gutter for that page count
  • Verify your gutter exceeds the minimum by at least 0.125”
  • Check that headers, footers, and page numbers are within margins
  • Verify mirror margins are enabled (gutter alternates left/right)
  • Re-export PDF and re-upload