Trim size
Also called: trim dimensions, book size
Definition
Trim size is the final physical dimensions of a KDP paperback after cutting, measured in inches (US) and rounded to 0.001 inch. The most common KDP coloring book trim sizes are 8.5 x 11 inches (standard letter), 8 x 10 inches (compact), and 8.5 x 8.5 inches (square). Trim size is set at title creation and cannot change later.
What is trim size on Amazon KDP?
Trim size is the finished dimensions of a printed paperback after the trimming step in production. It is set when the title is first created in KDP and cannot be changed afterwards. To switch trim sizes you must publish a new title with its own ASIN.
What trim size is best for a coloring book?
8.5 x 11 inches is the default coloring book trim. It matches US letter paper, gives the illustration room to breathe, fits on standard scanners and color printers, and is the size buyers expect when searching "coloring book" on Amazon. The most common alternative is 8 x 10 inches for a more compact format that prints cheaper.
How does trim size affect KDP print cost?
Trim size feeds into the page-count print cost tier. As of 2026 the standard fixed-cost tier is $2.30 per book for 24 to 108 black-and-white pages, then $1.00 base + $0.012 per page from 110 to 828 pages. Trim is largely orthogonal to per-page cost within the supported list, but unsupported trim sizes (anything outside KDP's published list) are simply rejected at upload.
Which trim sizes does KDP support?
The supported trim sizes are listed in the KDP help center under "Trim size" and include 8.5 x 11, 8 x 10, 8.25 x 11, 8.5 x 8.5, 7.5 x 9.25, 6 x 9, and roughly 30 others. Coloring books realistically use one of three: 8.5 x 11 (default), 8 x 10 (compact), 8.5 x 8.5 (square gift format).
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Related terms
Bleed
Bleed is the 0.125 inch (3.2 mm) extension of artwork past the trim line of a KDP paperback page. It exists so that small variations in the cutting machine do not produce a thin white sliver at the page edge. Coloring books with full-page line art must include bleed or risk KDP rejection.
Gutter
The gutter is the inside margin near the spine where two facing pages meet. KDP requires a minimum gutter margin that scales with page count: 0.375 inch for 24 to 150 pages, 0.5 inch for 151 to 400 pages, and 0.625 inch for 401+ pages. Putting critical art in the gutter leaves it hidden in the spine.
Spine
The spine is the bound edge of a paperback, including the visible spine strip on the cover. Spine width is calculated from page count: KDP's formula is page count x 0.002252 inch for white interior paper, x 0.0025 inch for cream. A 100-page coloring book has a 0.2252 inch spine on white paper.
Manuscript
The manuscript is the interior PDF file uploaded to KDP, distinct from the cover file. For coloring books, the manuscript contains all the line-art pages, any front matter (title page, copyright), and any back matter (about the artist, also-by). KDP requires a print-ready PDF at 300 DPI with embedded fonts and bleed.