KDP error guide
Check the true page size of your PDF
Read the PDF's real page boxes and compare them with the trim selected for the book.
Technically reviewed · September 1, 2026
What this issue means
Application labels are not proof of exported size. The check uses unrounded PDF points so a small but real mismatch is not hidden by display rounding.
What BookPreflight checks
- MediaBox, CropBox, TrimBox and BleedBox
- Mixed page sizes or rotations
- Declared trim versus actual page dimensions
How to correct the source file
- 1
Set the source page size to the chosen trim before layout.
- 2
Disable fit-to-page or printer scaling during export.
- 3
Recheck every page for accidental section-size changes.
Verify the exported PDF, not the preset name
Keep the editable source and original PDF. Export a new file, run the complete scan again and review every remaining finding. A repair is only labelled safe after loss checks and a full deterministic post-flight.
BookPreflight is an independent tool. It is not affiliated with or endorsed by Amazon or Kindle Direct Publishing, and it cannot guarantee acceptance.