How to Format a Book for KDP (2026): Margins, Fonts & Print-Ready PDF

Your first decision is selecting physical page dimensions, known as the trim size. Changing your trim size later will force you to reformat the entire book because line wraps, margins, and page counts will shift. Common trim sizes for Amazon KDP:

• 5 x 8" or 5.5 x 8.5": Standard for fiction, romance, and memoirs.
• 6 x 9": The most popular US paperback size, ideal for non-fiction and novels.
• 8.5 x 11": Best for workbooks, textbooks, and children's picture books.

You must also determine if your document requires bleed. If your images or background colors extend to the very edge of the page, you need bleed.

Learn more about this choice in our trim size guide or see how we configure trim sizes on our KDP formatting services page.

Margins keep your text from getting too close to the page edges. The inside margin (gutter) is especially critical because it prevents text from being swallowed by the book binding (the spine crease). As your page count increases, your spine gets thicker, requiring a larger gutter.

To calculate your exact spine width and verify margins, check out our KDP spine calculator tool before finalizing your layout.

Your book's front matter sets a professional tone. It includes the half title, title page, copyright page, dedication, and table of contents. Front matter pages should never have visible page numbers, or they should use Roman numerals (i, ii, iii) to distinguish them from the main text. Ensure your copyright page has all the necessary legal disclaimers, publisher info, and your ISBN. Need help organizing these first pages? Review our front matter copyright guide.

Apply consistent typography across your entire manuscript. Use paragraph styles rather than manual styling:

• Font Selection: Choose highly readable serif fonts like Garamond, Baskerville, or Sabon at 10pt to 11.5pt. Avoid sans-serif for long text blocks.
• Chapter Openings: Drop the first page of each chapter down by 2 or 3 inches to create breathing room. You can also use a drop cap (the first letter enlarged) for a professional look.
• Spacing: Set line spacing (leading) to 1.35x–1.5x of your font size to prevent eye strain. For a complete list of recommended typefaces, see our guide on best fonts for books in 2026.

Low-quality images are the leading cause of KDP file rejection or blurry prints. Always follow these rules:

• Resolution: Every image must be at least 300 DPI (dots per inch) at its final printed size. Images copied from web browsers are usually 72 DPI and will look pixelated.
• Color Mode: If printing in color, convert all images to CMYK color profile. For black-and-white, convert images to grayscale to avoid muddy print hues.
• Wrap Settings: In Word, set images to "In Line with Text" to prevent layout shifting when exporting. If you have illustrations that cover the whole page, read our understanding bleed guide to avoid cut-off details.

Page numbers must align with print conventions. For paperbacks:

• Page numbering should begin with Arabic numeral 1 on the first page of Chapter One (recto/right-hand page).
• Page numbers and running headers (book title/author name) must alternate on left (verso) and right (recto) pages.
• Never allow page numbers or headers on blank pages, title pages, or half-titles. Manually tweaking these in Word can be frustrating. Learn more about professional margins and page budgets in our advanced KDP formatting guide.

To publish a paperback on KDP, you must export your document as a print-ready PDF. Do not upload DOCX files directly, as formatting will shift on Amazon's servers. Use the following PDF export checklist to ensure your file passes validation:

• [ ] Export format is set to PDF/X-1a:2001 or PDF/X-3 (standard print-ready format)
• [ ] All fonts are 100% embedded (no subset or missing fonts)
• [ ] All images are high resolution (300 DPI at final print size)
• [ ] Color mode is CMYK for color printing, or Grayscale for B&W printing
• [ ] Crop marks are disabled (KDP does not want crop marks on interior files)
• [ ] Page count is an even number (add a blank page at the end if odd)

For a deeper look into PDF standards, review what is a print-ready PDF.

Log into your Kindle Direct Publishing account, select "Create Paperback" (or Hardcover), and fill out your book metadata (title, author, keywords, categories, and description). In the "Paperback Content" tab:

• Choose your ink and paper type (white vs cream).
• Choose your exact trim size and bleed options.
• Upload your print-ready interior PDF and your print-ready cover PDF.
• Ensure your cover PDF matches the exact spine width calculated from your formatted page count. Use our KDP spine calculator if you need to double-check the width.

Once your files upload, launch the online Print Previewer. This tool performs a digital check on your layout:

• Check the guides (dotted lines) representing trim margins and the safety zone. Any text outside the safety lines will trigger a rejection.
• Verify that images spanning page edges cross the bleed margin correctly.
• Check page numbers, headers, and the spine text alignment. Do not skip this step! Many layout issues that look fine in a PDF viewer become obvious in the previewer.

If the previewer flags issues, or if KDP sends a rejection email, don't panic. Common fixes include:

• "Fonts not embedded": Re-export your PDF ensuring "Embed All Fonts" is checked.
• "Text outside margins": Increase the gutter margin or pull headers closer to the center of the page.
• "Bleed error": Ensure your PDF canvas size includes the extra 0.125" width and 0.25" height. If you are tired of fighting technical rules and want guaranteed publication on the first attempt, explore our KDP formatting services to let our experts handle the heavy lifting.