Achieving a “flawless” status on your KDP submission requires strict adherence to Amazon’s exact technical specifications for print-on-demand files. The most common errors—incorrect margins, bleed issues, and resolution problems—lead to production delays, proofing nightmares, and even outright rejection. To ensure seamless submission, authors must precisely configure their interior PDF file to meet KDP’s core requirements before uploading.
Core KDP Interior File Specifications
KDP relies on an automated system to process thousands of books, meaning there is zero tolerance for deviation from their published standards. The three non-negotiable elements are Trim Size, Bleed, and Margins.
The Critical Calculation: Margins and the Gutter
Margins determine where your text block sits on the page and prevent text from being trimmed or pulled into the spine. The Gutter is the inner margin adjacent to the spine, and its size must increase with the book’s total page count.
| Page Count Range | Minimum Inner Margin (Gutter) | Minimum Outer, Top, Bottom Margins |
| 151 to 300 pages | 0.5” (1/2 in) | 0.25” (1/4 in) |
| 501 to 700 pages | 0.75” (3/4 in) | 0.25” (1/4 in) |
Final File Preparation Checklist
Once your layout is complete, ensuring the file type and resolution are correct is the final step to a successful submission.
Checklist for Interior Files:
- Format: Must be a single, print-ready PDF file.
- Resolution: All images (if applicable) must be at least 300 DPI (dots per inch) for high-quality printing.
- Color Space: Interior files should use grayscale for black-and-white books, or CMYK (recommended) or RGB for color books.
FAQ: KDP Submission Fine-Tuning
Q: What is the difference between inner margin and gutter?
A: They are functionally the same thing. The inner margin is the area closest to the book’s spine, often referred to as the gutter in publishing, because it is where the pages “meet” in the middle.
