What is trim size?
Trim size is a printed book's final width and height, measured after the pages are cut. KDP's own definition is “your printed book's width and height”. It sets the page count, the spine's width, part of the printing cost, and how the book feels in the hand.
What it means in practice
Choose the trim before you judge the page count: the same words take more pages on a smaller page. Page count in turn sets the gutter, the spine and the printing cost, which KDP works out from trim size, page count, ink and paper.
KDP treats 5.5 × 8.5 in and 6 × 9 in as regular trims. 7 × 10 in and 8.5 × 11 in are large trims, which print at a different cost.
How Chapbook uses it
A nonfiction book, workbook or guide has a Paperback interior row where you pick the trim. A book set on 6 × 9 in suggests that trim, and one on US Letter or A4 suggests 8.5 × 11 in.
The sample on this page is a digital PDF on a 6 × 9 in page, the size its paperback would start from. To see what the words come to, the free words to pages tool estimates a book’s pages from its word count.
In a real book
Sources
Last reviewed 30 October 2026
Related terms
- What is bleed in book printing? Bleed is artwork that runs past the cut line, so it reaches the page edge after trimming. KDP's bleed size, the page it makes, and when Chapbook adds it.
- What is the gutter in a book? The gutter is the inside margin of a printed page, the part closest to the binding. KDP's minimum by page count, and how Chapbook's paperback follows it.
- What is a book spine? The spine is the bound edge of a book, the part you see on a shelf. How KDP's paper and page count set its width, and when it can carry text.
Make one
Questions people ask
Which trim sizes does Chapbook offer for a paperback?
5.5 × 8.5, 6 × 9, 7 × 10 and 8.5 × 11 inches, each a KDP paperback trim. You pick one on the Paperback interior row, and the book is laid out again for it.
Does a digital PDF have a trim size?
No, because nothing is cut. A digital PDF has a page size. Chapbook starts a nonfiction book on 6 × 9 in and the other kinds on US Letter.
Read a chapter of your own book before you pay for it.
The outline, one sample chapter up to 2,500 words and a watermarked cover are free: 60 Book Credits on sign-up, no card.