One interior PDF can usually serve both platforms, because they agree on the things people worry about most: bleed is 0.125 inches on three edges, covers are a single CMYK PDF at 300 DPI, fonts must be embedded, and neither wants crop marks. Where they diverge is page count limits, accepted file types, the required PDF standard, and spine text. Those four differences are what actually cause a rejection.
If you are looking for the margin and gutter numbers rather than the file rules, they are in US print on demand book requirements.
The Four Real Conflicts
1. Page count limits
| KDP | IngramSpark | |
|---|---|---|
| Paperback minimum | 24 | 18 |
| Hardcover minimum | 75 | 18 |
| Paperback maximum | 828 | 1200 on 50lb white |
| Hardcover maximum | 550 | 840 |
The consequences are concrete. A 20 page book is publishable at IngramSpark and rejected outright by KDP. A 40 page hardcover is fine at IngramSpark and impossible at KDP. A 950 page novel can be a single IngramSpark paperback and cannot be a KDP paperback at all.
2. Accepted interior file types
KDP is permissive. Its paperback submission guidelines state that "You can upload your manuscript as a PDF, DOC, DOCX, RTF, HTML, or TXT file", converting them to PDF before printing, with a 650MB ceiling.
IngramSpark's print ready path is not. The File Creation Guide lists PDF as the required format, says "Text files must be submitted as a single PDF file: submissions with multiple files will be rejected", and names Microsoft Word among non supported programs.
The nuance worth knowing is that IngramSpark's newer Book Building Tool does accept a .docx interior. The Guide's restriction applies to the print ready PDF route, not to that tool.
3. The PDF standard
This is the conflict most likely to catch a careful author out, because both platforms are talking about PDF/X and still do not agree.
IngramSpark states a requirement: files must be PDF/X-1a:2001 or PDF/X-3:2002 compliant.
KDP states a preference: PDF/X is used and PDF/X-1a is preferred, and warns that non PDF/X files such as PDF/A may have comments, forms and other non printing objects removed during review.
They agree that PDF/X-1a is the safe answer. What makes this messy is that KDP's own Word walkthrough instructs you to tick the PDF/A compliance box when saving, producing exactly the file type KDP's submission page warns about and that IngramSpark does not accept at all. Following KDP's beginner path produces a file outside IngramSpark's stated spec.
4. Spine text minimums
KDP: "We only print spine text on books with more than 79 pages."
IngramSpark: since a change dated 23 April 2026, hardcovers carry spine text from 18 pages and paperbacks from 48 pages.
So a 60 page paperback gets a printed spine at IngramSpark and a blank spine at KDP, and your cover file has to account for that difference rather than assume it.
Two Traps in the Documentation Itself
IngramSpark contradicts itself on bleed. The File Creation Guide says bleed goes on three edges and warns "Please do not add bleed to the bind (gutter) edge as this will cause incorrect positioning". A help centre article on common file issues says full page designs should have bleed "around all edges". The Guide is the authoritative document. Follow the three edge rule, or your pages sit off centre.
Resolution floors are not what people assume. KDP states a flat 300 DPI minimum and recommends a 600 DPI maximum. IngramSpark recommends 300 ppi but sets its actual rejection floors much lower, rejecting interior colour images under 72 ppi and cover images under 200 ppi. IngramSpark alone also specifies 600 ppi for 1-bit line art and grayscale conversion for black and white interiors, neither of which KDP addresses.
The Gutter Problem for a Dual Platform File
There is no single inside margin that satisfies both platforms across all page counts.
KDP enforces a banded gutter that grows from 0.375 inches to 0.875 inches as the page count rises. IngramSpark recommends a flat 0.5 inches on all sides plus an extra 0.125 inch white strip on the bind edge, with no page count banding at all.
A 24 to 150 page book built to KDP's legal 0.375 inch gutter sits below IngramSpark's recommendation. A 700 page book needs 0.875 inches at KDP while IngramSpark still asks only for 0.5. The flat 0.5 inch value only satisfies both in the 151 to 300 page band.
The practical rule: take the larger of IngramSpark's 0.5 inches and KDP's band for your page count, and add the 0.125 inch bind strip. That clears both. The same logic applies to outside margins, where KDP's floor of 0.25 inches is half IngramSpark's 0.5 inch recommendation.
Where They Agree
Useful, because it is most of the file:
- Bleed is 0.125 inches, added to top, bottom and outside only. A 6 by 9 interior with bleed is built at 6.125 by 9.25 at both.
- Interior bleed is optional at both, needed only when art runs to the page edge.
- The cover is a single PDF containing back cover, spine and front cover as one spread.
- Covers are CMYK at 300 DPI, and both platforms discourage embedded ICC or spot colour profiles.
- All fonts must be embedded.
- No crop marks, no reader spreads, single page PDF.
- Both supply a cover template generator keyed to trim size and page count.
What Deckle Exports
Deckle's print PDF is built for exactly these rules.
Bleed is applied on three edges only. The export widens the page by the bleed amount on the outside edge and by twice the bleed vertically, leaving the spine edge untouched. A 6 by 9 book comes out at 6.125 by 9.25, which is what both platforms specify and what IngramSpark's gutter warning requires.
The gutter is enforced against KDP's bands automatically. Deckle takes the larger of your inside margin and the KDP minimum for the estimated page count, so a long book cannot be exported with a gutter that KDP would reject. It does not add IngramSpark's extra 0.125 inch bind strip, so if you are printing through IngramSpark, set your inside margin 0.125 inches higher than you otherwise would. See book margins and gutter explained.
Fonts are embedded in the exported PDF, satisfying the requirement both platforms state.
The PDF is not PDF/X. Deckle produces a standard PDF rather than a PDF/X-1a or PDF/X-3 file. Against KDP's stated preference this is a soft point. Against IngramSpark's stated requirement it is a difference you should know about before you upload, and converting the exported PDF to PDF/X-1a in Acrobat or a preflight tool is the way to close it if IngramSpark's preflight objects.
Deckle does not produce cover files. The cover is a separate job for a design tool, using the template generator the platform gives you, and the spine measurement in how to calculate spine width.
For the full spec of each platform, see KDP print file requirements and IngramSpark file creation requirements. For how the bindings themselves differ, see hardcover vs paperback specifications, and for whether to use these platforms at all, print on demand vs offset printing.
Common Mistakes
- Assuming one file clears both. Page count limits and the PDF standard are where it breaks.
- Following KDP's PDF/A instruction and uploading to IngramSpark. PDF/A is not on IngramSpark's accepted list.
- Adding bleed to the gutter edge. Three edges only, or the pages sit off centre.
- Designing to KDP's 0.25 inch outside margin. Half of what IngramSpark recommends.
- Assuming your spine will carry text. Under 80 pages it will not at KDP.
- Trusting IngramSpark's help centre over the File Creation Guide. They contradict each other on bleed.
FAQ
Q: Can I upload the same interior PDF to both? A: Usually yes, if you build to the larger of the two margin sets and the book is within both page count ranges. The PDF standard is the remaining gap.
Q: Which platform is stricter? A: IngramSpark on file format and PDF standard. KDP on page counts and gutter enforcement.
Q: Does IngramSpark really reject Word files? A: On the print ready PDF path, yes. The Book Building Tool accepts a .docx interior.
Q: Do I need PDF/X-1a? A: IngramSpark states it as a requirement. KDP prefers it. Converting to PDF/X-1a costs nothing and removes the question.
Q: Why does IngramSpark accept an 18 page book when KDP needs 24? A: Different presses and binding lines. There is no deeper reason and no way to argue either number.