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Trim size

Printing & file preparation

Also called: book size, trim

The finished width and height of a printed book after the pages are cut. KDP publishes a catalog of standard trim sizes, and the one you pick affects both layout and printing cost.

Trim size is what you would measure with a ruler on a copy of the finished book. It is chosen before you lay out the interior, because every margin, image, and line length depends on it, and changing it later means redoing the layout.

KDP splits its catalog into standard and large trims at 6.12 inches wide and 9 inches tall. That boundary is not cosmetic: standard and large trims use different printing-cost tables, so two visually similar sizes can cost meaningfully different amounts per copy. 6 × 9 inches is standard; 6.14 × 9.21 is large.

Not every trim supports every format. Only five of KDP's sizes are available in hardcover, so if a hardcover edition matters to you it should influence the trim decision from the start.

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SmartKDP is not affiliated with, endorsed by, or sponsored by Amazon. Amazon, Kindle, and Kindle Direct Publishing are trademarks of Amazon.com, Inc. or its affiliates.

Related terms

  • Spine width

    How thick the book's spine is — page count multiplied by a per-page paper thickness, plus a fixed board offset on hardcovers. It determines where the fold lines sit on your cover file.

  • Gutter margin

    Extra inside margin that compensates for the part of the page swallowed by the binding. KDP's required gutter grows with page count, because thicker books open less flat.

  • Printing cost

    What Amazon charges to manufacture one copy, deducted from every sale before your royalty. It is a fixed amount plus a per-page amount, set by marketplace, ink type, and trim category.

  • Bleed

    Extra artwork extended past the trim line so that ink still reaches the edge of the finished book after cutting. KDP's bleed is 0.125 inches — on every outer edge of a cover, but on only three edges of an interior page.