KDP Trim Sizes — A Complete Guide

Every approved size, and which one to pick for your book.

Short answer: The complete KDP trim size guide: every approved size from 5×8 to 8.5×11, which to pick for which book type, and how to set it in your manuscript.

Reference · Updated for 2026

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What a Trim Size Is

Trim size is the finished size of your printed book. You choose it when you set up a KDP title, and it drives your cover dimensions, interior margins, page count and print cost. Picking the right one is a small decision with a big effect on how professional the book feels.

The Common Sizes and What They’re For

5" × 8" — novels, fiction; standard for fiction series.
5.5" × 8.5" — trade paperbacks, self-help.
6" × 9" — the most common non-fiction and journal size.
6.69" × 9.61" — the standard “industry” size many authors default to.
7.5" × 9.25" — textbooks, academic, manuals.
8" × 10" — workbooks, activity books.
8.5" × 8.5" — coloring books, children’s picture books.
8.5" × 11" — planners, log books, large workbooks.
5.06" × 7.81" / 5.25" × 8" / 5.83" × 8.27" — smaller fiction/paperback options.
6.14" × 9.21" / 7" × 10" / 7.44" × 9.69" / 8.25" × 6" / 8.25" × 8.25" — less common but approved.

How to Choose

Match your category — look at the top books in your niche and mirror their trim size.
Journals/planners — 6" × 9" or 8.5" × 11" depending on writing room.
Coloring/picture books — 8.5" × 8.5" square reads best.
Novels — 5" × 8" or 5.5" × 8.5" keeps print cost down.
Bigger ≠ better — larger trim sizes cost more to print, which cuts your royalty.

Setting It in KDP

During title setup, pick the trim size from KDP’s dropdown, then export your manuscript at exactly that size. The KDP Cover Calculator will then generate the cover dimensions from trim size + page count + paper type. Check the cover dimensions guide for the ratio.

FAQ

What is the most common KDP trim size? 6" × 9" is the most common overall; novels often use 5" × 8" or 5.5" × 8.5".

Can I change trim size after publishing? Only by creating a new edition — choose carefully before uploading.

Does trim size affect royalty? Yes — bigger sizes cost more to print, lowering your paperback royalty.

Where do I check the full list? KDP’s print setup shows all approved sizes; the list above covers the common ones.

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