Formatting is where a lot of first-time authors lose momentum. The writing is done, and then Amazon's Kindle Direct Publishing (KDP) asks for trim sizes, bleed, mirrored margins, and validated files — and a single wrong number sends the upload back. This guide walks through the whole checklist in plain English, so your paperback and eBook go up cleanly the first time.

1. Choose your trim size first

Everything downstream — margins, page count, spine width — depends on your trim size (the finished dimensions of the printed book). Pick it before you format anything. The safe default for most fiction and non-fiction is 6 × 9 inches; novellas and poetry often use 5 × 8; workbooks and cookbooks go larger, up to 8.5 × 11. Choose the size readers in your genre expect, then commit to it. (Inkbound supports eight common KDP trim sizes and recomputes the layout when you pick one.)

2. Get margins, gutter, and bleed right

Print isn't forgiving, so three measurements matter:

  • Outer margins keep text from crowding the edge — roughly 0.5–0.75 in is typical.
  • Gutter is the extra inner margin near the spine. It grows with page count, because thicker books curve more at the binding. Skip it and text disappears into the spine.
  • Bleed (0.125 in past the trim) is only needed if images or color run to the edge of the page.

Margins should also mirror — left and right pages are mirror images so the gutter is always on the binding side. Most word processors don't do this well, which is the number-one giveaway of a self-published interior.

3. Typeset the interior like a real book

A professional interior follows conventions readers feel without naming: running heads (author and title at the top), folios (page numbers) that suppress on chapter-opening pages, chapters that begin on a fresh right-hand page, and a tasteful drop cap or scene-break ornament. Use a book-grade serif for body text, set a comfortable size and leading, and keep it consistent throughout. This is exactly the work Inkbound's formatting templates handle automatically.

4. Build a KDP-exact cover

For the paperback you need a single full-wrap file — back, spine, and front together — at 300 DPI with 0.125 in of bleed. The spine width is calculated from your final page count and paper stock, so finish your interior before you finalize the cover. The eBook needs only a front-cover image. Getting the wrap dimensions wrong is the most common cause of a rejected upload; Inkbound's cover lab does the spine math and bleed for you.

5. Export the files KDP actually wants

KDP accepts two files you'll generate from the same manuscript:

  • A print-ready PDF at your exact trim, with embedded fonts and mirrored margins, for the paperback.
  • A reflowable EPUB 3 for the Kindle eBook.

Validate the EPUB before uploading — an invalid file is an instant bounce. Inkbound exports both and runs a pre-flight check so nothing comes back at upload.

6. Prepare your metadata before you upload

Formatting gets the book accepted; metadata gets it found. Before you open the KDP dashboard, draft your book description, fill all seven keyword slots, and choose your browse categories deliberately. On Amazon, this is where discoverability is won or lost — don't type it under pressure at the last minute.

The finished book should feel like it came from a publishing house — consistent from the first page to the metadata on its listing.

The shortcut

You can assemble all of this from separate tools — a word processor, a design app, a cover template, a validator — and reconcile them by hand every time something changes. Or you can do it in one place. Inkbound keeps writing, interior design, cover, and export in a single desktop studio, so your trim size, page count, spine width, and metadata always agree. See how it works →