Best PDF Settings for Amazon KDP Paperback Publishing
Amazon KDP Print is the most accessible way to publish a physical paperback — no upfront cost, print on demand, worldwide distribution. But KDP is strict about PDF specifications. Upload a file with incorrect trim size, missing bleed, or low-resolution images, and it will be rejected with a cryptic error. This guide gives you the exact settings that pass KDP validation on the first try.
Trim Size — Choose Before You Format
The trim size is the final dimensions of your printed book after the pages are cut. KDP supports many standard sizes. The most common: 5 x 8 inches — compact, popular for fiction. 5.5 x 8.5 inches — slightly larger, common for non-fiction. 6 x 9 inches — the most popular size overall, works for both fiction and non-fiction. 8.5 x 11 inches — workbooks, manuals, and textbooks.
Choose your trim size before you start formatting. Changing it later means reflowing your entire document. Your PDF page size must exactly match the trim size — KDP does not resize or crop your pages. If you select 6 x 9 inches, your PDF pages must be exactly 6 x 9 inches.
Bleed Settings
Bleed is extra space beyond the trim edge that gets cut off during printing. It prevents white edges on pages where colour or images extend to the edge. If your book has images, coloured backgrounds, or any element that touches the page edge, you need bleed. KDP requires 0.125 inches (3.175 mm) of bleed on the top, bottom, and outside edge.
With bleed enabled, your PDF page size is larger than the trim size. For a 6 x 9 inch book: pages are 6.25 x 9.25 inches. For text-only books (no images or elements touching edges), you can select "no bleed" in KDP setup — your PDF pages then match the trim size exactly, which simplifies formatting.
Margins — The Safe Zone
KDP has minimum margin requirements that vary by page count. For books under 150 pages: inside (gutter) margin: 0.375 inches, outside margin: 0.25 inches, top and bottom: 0.25 inches. For books 150-400 pages: inside margin: 0.5-0.625 inches (the spine is thicker, so more gutter space is needed for readability). For books over 400 pages: inside margin up to 0.875 inches.
In practice, use more generous margins than the minimums. Recommended margins for a 6 x 9 book: inside 0.75 inches, outside 0.5 inches, top 0.5 inches, bottom 0.5 inches. These provide comfortable readability and pass validation easily. Keep all body text, images, and page numbers within these margins.
Font and Image Requirements
Fonts: All fonts must be embedded in the PDF. Do not use system fonts without embedding — if the font is missing, KDP substitutes a generic font and your layout breaks. In most design tools, there is an option to embed all fonts when exporting to PDF. Minimum body text size: 7pt (but 10-12pt is recommended for comfortable reading). Do not use colour fonts for body text — KDP Print uses black ink for interior pages unless you select the premium colour option.
Images: All images should be at least 300 DPI at their printed size. An image that will print at 4 x 3 inches needs to be at least 1200 x 900 pixels. For black-and-white interiors, convert images to grayscale — colour images in a B&W book may look washed out because the printer converts them at print time. For the cover, KDP provides a template calculator that generates exact dimensions based on your trim size and page count.
PDF Export Settings
When exporting your PDF, use these settings: PDF standard: PDF/X-1a:2001 (preferred) or high-quality print PDF. Colour space: CMYK for colour interiors, grayscale for B&W. Resolution: 300 DPI minimum for images. Font embedding: Embed all fonts (subset or full). Transparency flattening: Flatten all transparency. Compression: Use lossless or high-quality JPEG compression for images — do not use maximum compression.
In Adobe InDesign: File > Export > Adobe PDF (Print) > Select PDF/X-1a:2001 preset. In Microsoft Word: File > Save As > PDF > Options > ensure "Optimize for print" is selected. In Google Docs: this is not ideal for KDP — Google Docs PDF export does not give you control over DPI, bleed, or colour profiles. Use a dedicated design tool for professional results.
Common Rejection Reasons
Page size does not match trim size: Your PDF pages must exactly match the trim size (plus bleed if enabled). Low-resolution images: Any image below 300 DPI at print size triggers a warning or rejection. Text outside margins: Page numbers, headers, or body text extending into the minimum margin area. Missing fonts: Un-embedded fonts that default to substitutes. Transparency issues: Unflatted transparency can cause printing artefacts. Always flatten before uploading.
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