KDP rejects PDF cover files even when they look fine? Check page size, white borders, crop marks, template lines, hidden objects, fonts, images, and export settings.
If KDP rejects PDF cover files even when they look fine, do not keep exporting the same PDF and uploading it again. A KDP PDF cover rejected after export can still have a file problem. KDP is not only looking at the design on screen. It is checking the final PDF file you submit.
A PDF can look normal in Canva, Preview, Acrobat, or KDP Previewer and still contain problems KDP cares about: wrong page size, white borders, crop marks, leftover template lines, hidden objects, transparency issues, missing embedded fonts, soft images, comments, placeholder text, or converter-added margins.
If you are not sure the problem is really PDF-specific, start with the broader Canva cover rejected by KDP checklist. This article is narrower: it is for the moment when the cover PDF looks okay, but KDP still rejects the cover or shows a preview problem.
Start with the exported PDF, not the Canva design or source file.
| What to check | Acceptable | Warning sign | What to fix |
|---|---|---|---|
| PDF page size | Matches KDP's current full cover size | Front-cover size, A4, Letter, old full cover size, or scaled output |
| Fix the source canvas or export route |
| Visible edges | No white border where artwork should reach the edge | White strip appears on one side or corner | Fix bleed or export scaling in the source file |
| Crop / trim marks | No crop marks, trim marks, color bars, or printer marks | Any print marks are visible in the final PDF | Export a clean upload file |
| Template content | No KDP template text, guide lines, labels, or software references | Template layer or guide text remains visible | Hide/remove guides before export |
| Fonts and images | Fonts and images render the same across viewers | Text changes, disappears, shifts, or images look soft | Re-export, embed, simplify, or replace assets |
| Transparency / layers | Effects render consistently | Shadows, transparent overlays, or objects shift or disappear | Test a flattened PDF and inspect it |
| Hidden objects | No invisible objects, comments, old guides, or placeholder text remain | KDP flags objects/margins you cannot see | Clean the source file or rebuild from a clean file |
| Converters | Output keeps exact dimensions and no margins | Converter adds margins, A4/Letter size, compression, or zoom | Avoid the converter or verify the final PDF |
If KDP gives you a specific warning, follow that warning first. This guide is for PDF-file issues, not every KDP rejection.
The visual preview is only one part of the file.
KDP's Paperback Submission Guidelines mention requirements such as embedded fonts and images, flattened transparent objects, no crop marks or trim marks, no comments, no invisible objects, and no placeholder text. KDP's paperback cover guidance also tells authors to remove crop marks, color bars, template text, PDF creation guides, and software references before upload.
That means a PDF can fail for two different reasons:
| Problem type | What it looks like | Example |
|---|---|---|
| Visible problem | You can see it when you open the PDF | White border, crop marks, template line, shifted cover |
| File-structure problem | The PDF may look normal, but KDP reads something inside the file | Hidden layer, invisible object, comment, transparency, missing embedded font |
KDP Previewer is useful, but it is not final approval. KDP's formatting guidance treats preview as one review step. If a later review email rejects the cover, read that email and recheck the final PDF.
Before checking layers or export settings, confirm the page size of the actual PDF you uploaded.
For a KDP paperback, the PDF page size should match the current full cover size: back cover, spine, front cover, and bleed in one file. If the PDF is A4, Letter, front-cover size, or an old cover size, KDP can reject it even if the artwork looks polished.
Check this:
| Where to look | Acceptable | Warning sign | What to fix |
|---|---|---|---|
| PDF properties | Page size matches the current KDP full cover size | PDF is front-cover size, A4, Letter, or an old size | Fix the source size or export route |
| KDP template | Current template matches the exported PDF | Template edges, spine, or barcode area do not line up | Generate a current template and re-export |
| Converter output | Final PDF preserves exact dimensions | Converter adds margins, scaling, zoom, or default page size | Use another route or inspect the output before upload |
A JPG-to-PDF case shows this well. The user was trying to create an exact-size PDF, but different tools added margins, scaling, A4 sizing, or unexpected zoom. The user eventually found a path that produced the right PDF size. The broader lesson is simple: check the final PDF page size, not only the source image or design.
If KDP gives you both expected cover size and submitted file size, use the expected vs submitted cover size guide before changing anything else.
You can also use the KDP Cover Size Calculator to compare the PDF page size against the current full cover dimensions.
Next, inspect the PDF visually at full page view and zoomed in around the edges.
| Where to look | Acceptable | Warning sign | What to fix |
|---|---|---|---|
| Outside edges | Artwork reaches where it should, with no unexpected white strip | Thin white border appears after export | Return to the source file and fix bleed/export scaling |
| Corners | Corners are filled when artwork should reach the edge | Corners show paper color or transparent gaps | Extend artwork or fix export route |
| Crop / trim marks | Final upload PDF has no marks | Crop marks, trim marks, printer marks, or color bars are visible | Export a clean PDF without marks |
| Template layer | No template text, red/blue guides, labels, or software references | KDP template is still visible | Hide or remove the template layer |
| Cover order | Back, spine, and front appear in the correct order | Barcode area or back cover appears on the front side | Re-align to the KDP template |
A white border can mean missing bleed, export scaling, or a PDF route that changed the page. If KDP specifically mentions 0.125 or the trim line, use the KDP cover bleed guide. If the PDF itself is the wrong size, fix size first.
Some PDF problems show up only after upload or preview.
KDP's submission guidance calls out embedded fonts and images. If text or images are not embedded or render differently, the local PDF can look fine while KDP reads or renders it differently.
Use this check:
| Where to look | Acceptable | Warning sign | What to fix |
|---|---|---|---|
| Text rendering | Text looks the same in multiple PDF viewers | Font changes, text shifts, text disappears, or spacing changes | Re-export, embed fonts, or simplify text |
| Image rendering | Images stay sharp enough for print | Image looks soft, pixelated, compressed, or missing | Replace low-quality image and export again |
| Effects around text | Shadows and overlays stay stable | Effects shift or hide text in Previewer | Simplify effects or test a flattened PDF |
| Back cover copy | Blurb and author bio remain readable | Thin text becomes faint or jagged | Use cleaner text styling or higher-quality export |
Do not fix a font or image problem by stretching the PDF. Fix the source file and export a new PDF.
This is the part that makes “but it looks fine” frustrating.
A PDF can include objects you do not notice: hidden layers, invisible boxes, comments, old template data, transparent shapes, or leftover elements outside the visible design. KDP may still read those objects.
One hidden-layer case fits this pattern: the PDF reportedly looked normal locally, but KDP flagged text or objects outside margins. The user later said support identified hidden layers or data, and cleaning the file helped. Treat this as one troubleshooting path, not proof that every PDF rejection is caused by hidden layers.
Check for these issues:
| Where to look | Acceptable | Warning sign | What to fix |
|---|---|---|---|
| Hidden objects | No invisible boxes, old guides, or off-page elements remain | KDP flags objects/margins you cannot see | Clean the source file or rebuild from a clean file |
| Comments / annotations | None remain in the upload PDF | Comments, notes, or review annotations exist | Remove comments before export |
| Placeholder text | No template wording remains | Template labels or placeholder words remain | Remove before export |
| Transparency | Transparent objects render consistently | Shadows, overlays, or translucent elements shift/disappear | Test a flattened PDF |
| Layers | Final file is simple enough to render consistently | Objects appear/disappear between viewers | Flatten, simplify, or rebuild |
If you cannot find the object KDP is flagging, start with the simple cleanup: remove comments and annotations, delete old template layers, check for invisible or off-page elements, and export a fresh PDF. If the file still behaves strangely, rebuild from a clean source instead of trying to rescue the same PDF.
Canva's flattened PDF guidance can be useful when layers or transparency might be the problem. But flattening is only a test. After flattening, inspect page size, edges, text, and image quality again.
Canva is not the default cause. KDP reviews the final PDF.
If the PDF came from Canva, keep the check focused on the exported file:
| Canva export area | Acceptable | Warning sign | What to fix |
|---|---|---|---|
| PDF type | PDF Print used as a print-oriented starting point | PDF Print treated as automatically KDP-ready | Inspect the final PDF before upload |
| Crop marks and bleed | Bleed used during design; final upload is clean | Crop marks or guide marks appear in the upload PDF | Export a clean final file |
| Flattened PDF | Tested when layers/transparency may be an issue | Treated as a universal fix | Compare flattened output carefully |
| Exported page size | Matches the KDP full cover size | Canva source looks right, but PDF properties are wrong | Fix source size/export route |
Canva's download file type guidance describes PDF Print as a print-oriented option. That is useful, but it does not make the file automatically ready for KDP.
If you need the full Canva setup process, use the Canva to KDP paperback export guide. This article assumes you already exported the PDF and now need to inspect what KDP received.
Once you know the first real problem, choose the smallest useful fix.
| Situation | Better next step |
|---|---|
| PDF page size is wrong | Fix the source canvas or export route, then compare with the KDP Cover Size Calculator |
| White border appears | Fix bleed/artwork in the source file or export route |
| Crop marks or template marks remain | Remove guide/export marks and export a clean PDF |
| Text or images disappear | Test embedding, flattening, or simpler effects |
| KDP flags hidden objects | Clean the source file or rebuild from a clean file |
| Converter keeps changing the PDF | Avoid the converter or verify output before upload |
| Source file is missing or too messy | Rebuild the full cover from current KDP settings |
If you only have a front cover, lost the source file, or cannot confidently remove hidden/template objects, rebuilding may be faster than another export. The KDP Book Cover Generator can help you create a new KDP cover draft from a cleaner starting point.
Do not keep uploading the same PDF and hoping KDP reads it differently. Find the first mismatch, fix it in the source or rebuild, then export a new clean PDF.
Because KDP checks the final PDF file, not only the visible design. The file may have the wrong page size, hidden objects, crop marks, template text, transparency issues, missing embedded fonts, low-quality images, or converter-added margins.
No. PDF Print is a useful print-oriented starting point, but you still need to check the final PDF page size, bleed, safe area, visible marks, fonts, images, transparency, and hidden objects.
No. KDP's submission guidance says submitted files should not contain crop marks or trim marks. Use guides while designing if they help, but upload a clean final PDF.
No. Flattening can help test some layer or transparency issues, but it does not fix wrong page size, missing bleed, unsafe text, barcode overlap, low image quality, metadata issues, or policy issues.
Read the review email and follow the exact issue it names. Previewer is useful, but it is not a final approval guarantee. If the email mentions PDF objects, marks, text, images, or file quality, inspect the final PDF again.
Fix or rebuild the source file when the PDF structure or page size is wrong. Resizing a finished PDF can distort the cover, move the spine or barcode area, reduce image quality, and hide the real problem.