KDP trim size recommender
Publishing glossary
Trim size: the final dimensions of your printed book.
Trim size is the finished page width and height of a printed book after the block is cut.
Checked:
✓6x9 inches is the KDP standard✓Page count changes with trim size✓The cover must match the trim size
Choosing a trim size
Fiction usually uses 5x8 or 5.5x8.5, nonfiction and workbooks use 6x9 or larger. The trim size fixes the page dimensions for both interior and cover.
- Pick the size before formatting
- Changing size reflows the whole book
- Trim size sets the spine calculation
Getting the dimensions right
The book sizes tool lists KDP's accepted trim sizes with page counts, and the cover calculator derives the matching wrap from the size you choose.
Why trim is decided before the budget
Every copy of a paperback is cut from a web press sheet, so the trim size fixes the print cost per page and the page-count range Amazon accepts. A 6x9 book at 400 pages and a 5.5x8.5 book at 400 pages have different costs, spines, and royalty outcomes — changing size after formatting reprints the layout and re-runs the budget. Pick size from the page-count tables, then confirm the spine width before you approve the cover file.
- Amazon accepts a page-count range per size, not every size for every count
- Spine text below 80 pages is not recommended for paperback
- Children's books and large-print books use different size sets entirely
FAQ
Frequently asked questions
What is the most common KDP trim size?
6x9 inches for nonfiction and novels, with 5.5x8.5 as a close second for fiction.
Can I change trim size after formatting?
You can, but every page reflows. Choose the size first, then format once.
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