01
RejectedWhite edge after upload preview
Your 8.5 x 11 interior was exported without the extra 0.125" bleed, so artwork stops at the trim line.
Actual
Actual 8.5" x 11"
Expected
Expected 8.625" x 11.25"
Bleed warning
Free KDP Preflight Tool for Amazon Creators
Fix bleed, trim, spine, and margin issues before KDP rejects your upload.
Scan your cover and manuscript PDF for practical KDP problems: bleed, trim size, spine width, safe areas, margins, and export mistakes that create painful Amazon KDP upload errors.
Files processed locallyNo manuscript storageBuilt for KDP creators
Real upload mistakes
Real KDP upload mistakes creators run into.
The file can look finished in Canva, Preview, Acrobat, Affinity, or Illustrator and still fail because the final PDF does not match what KDP measures.
02
Check fileCover PDF does not match the selected trim
The cover looks correct in Canva, but the final PDF is 0.08" too narrow for the spine and bleed.
Actual
Cover width off
Expected
Spine + bleed missing
Trim mismatch
03
Fix before uploadPage count changed after your cover was designed
A 300-page white-paper paperback needs about 0.676" of spine. Small page count changes move the cover wrap.
Actual
White paper
Expected
0.002252" per page
Spine risk
04
Pass after fixBarcode and back-cover text sit too close to trim
Important cover content is inside the cut-risk area instead of staying within KDP safe margins.
Actual
Text inside risk zone
Expected
Keep 0.25" safe area
Safe area
The workflow
Problem, scan, issue, fix, confidence.
KDPPreflight works like a production workstation: calculate the specs, scan the exported files, identify the issue, then preview the corrected book.
01Smart Book Setup
Calculate Exact KDP Specs
Enter trim size, page count, paper type, and cover format to get KDP cover dimensions, bleed, spine width, margins, and safe area before export.
KDP trim size calculator
KDP spine width calculator
Bleed margin guide
02Format Checker
Check Your Exported Files
Scan your cover PDF and manuscript PDF for KDP upload errors: missing bleed, wrong trim, unsafe margins, low resolution images, and spine mismatch.
KDP bleed checker
KDP manuscript checker
Actual vs expected measurements
033D Book Preview
Preview the Physical Book
Inspect the paperback or hardcover as a physical object after the files pass the production checks.
Paperback and hardcover preview
Spine inspection
Export preview images
A real KDP bleed checker result
Understand exactly what is wrong.
A practical result should show the selected issue, highlighted bleed edge, actual vs expected measurements, and the export setting that fixes it.
Inspection result
Page 2 bleed is incomplete.
KDPPreflight turns a vague paperback bleed issue into the exact measurement to fix.
Actual file8.5" x 11"
Expected with bleed8.625" x 11.25"
Fix previewExport with bleed enabled
Bleed edge selectedFix preview ready
Private creator workstation
Your unpublished files never leave your browser.
KDP creators upload manuscripts they have not published yet, covers they paid for, and interiors they plan to sell. KDPPreflight treats those files like private production assets, not sample data.
Your unpublished files never leave your browserNo cloud upload requiredNo AI trainingNo manuscript storageNo cover storageLocal processing whenever possible
KDP formatting guide
KDP bleed, trim size, spine width, and PDF upload errors explained.
Practical KDP measurements and examples for creators who want to catch rejection risks before they upload.
Check the 0.125" bleed before KDP does
Paperback interiors with bleed need 0.125" added to the outside, top, and bottom edges. For an 8.5 x 11 trim, a full-bleed page should export as 8.625" x 11.25", not 8.5" x 11".
Match the PDF to the trim size selected in KDP
A trim mismatch happens when your uploaded PDF dimensions do not match the book size in the KDP setup screen. KDPPreflight compares the exported file to practical trim targets like 6 x 9, 8 x 10, and 8.5 x 11.
Calculate spine width from paper type and page count
Spine width changes with white paper, cream paper, color interiors, and page count. A 300-page white-paper paperback is about 0.676" wide, while cream paper uses 0.0025" per page.
Find manuscript bleed and margin problems
Interior PDFs can fail because pages mix sizes, artwork reaches the trim without bleed, or body text sits in unsafe margins. The checker highlights the page and measurement that caused the risk.
Build the full cover wrap, not just the front cover
A paperback cover PDF must include back cover, spine, front cover, and 0.125" bleed on all sides. Missing the spine or bleed is one of the most common Amazon KDP upload errors.
Turn vague upload errors into fixable measurements
KDP errors often say the file is the wrong size without explaining the source. KDPPreflight breaks the problem into actual dimensions, expected dimensions, and the export setting to check next.
FAQ
Questions self-publishers ask after KDP rejects a file.
Specific answers for KDP cover checker, KDP manuscript checker, KDP bleed checker, trim mismatch, PDF export, Canva, Affinity Publisher, and Adobe Illustrator workflows.
Why does Amazon KDP reject PDFs that look correct?
KDP validates exact PDF dimensions, bleed, trim size, margins, image resolution, and cover wrap math. A PDF can look correct in Preview, Canva, Acrobat, or Affinity Publisher and still be 0.05" off from the KDP cover dimensions required for upload.
What is a KDP bleed issue?
A KDP bleed issue means artwork or background color reaches the trim edge but the PDF does not include the required extra bleed area. For most bleed layouts, add 0.125" beyond the trim so cutting does not leave white edges.
How do I fix a KDP trim mismatch?
Confirm the trim size selected in KDP, then export the manuscript and cover to the exact expected size. For example, an 8.5 x 11 manuscript without bleed should be 8.5" x 11"; with bleed it should include the extra bleed dimensions.
Can KDPPreflight check manuscript bleed?
Yes. The KDP manuscript checker compares page boxes and dimensions to your selected trim and bleed mode so you can find paperback bleed issues before upload.
How is KDP spine width calculated?
Spine width depends on page count and paper type. White paper uses about 0.002252" per page, while cream paper uses about 0.0025" per page. The KDP spine width calculator applies those values to your book specs.
Why do low-resolution images cause KDP upload errors?
Images below roughly 300 DPI can print soft or trigger quality warnings. A useful KDP PDF checker should flag low resolution artwork before you upload the cover or manuscript.
Can Canva exports create KDP cover size problems?
Yes. Canva designs can export at the wrong page size if the document was created from a front-cover canvas instead of a full paperback wrap. Check the final PDF width, height, bleed, and spine before uploading.
Can Affinity Publisher exports fail KDP checks?
Yes. Affinity Publisher files can fail if bleed is set in the document but not included during PDF export, or if the PDF preset changes page boxes. Recheck actual vs expected dimensions after export.
Can Adobe Illustrator cover PDFs fail KDP checks?
Yes. Illustrator exports can use the artboard size instead of the full bleed box, flatten artwork unexpectedly, or omit the 0.125" bleed. Validate the exported PDF, not only the design file.
Does KDPPreflight store my unpublished files?
No. KDPPreflight is designed as a private creator workstation with local browser processing whenever possible. No manuscript storage, no cover storage, and no AI training on your book files.
Before the next upload
Your PDF looks fine until KDP checks it.
Catch the bleed, trim, spine, margin, and PDF export issue before it becomes another rejected upload.