Book sizes: standard trim sizes and how to choose one
The most common paperback book sizes are 5 × 8, 5.5 × 8.5 and 6 × 9 inches, with 6 × 9 the default on Amazon KDP. Larger trims — 7 × 10 and 8.5 × 11 — suit workbooks, manuals and illustrated books. KDP also accepts custom sizes from 4 to 8.5 inches wide and 6 to 11.69 inches tall. The trim you choose changes the page count, the spine width and the cover dimensions, so pick it before you format the interior.
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Standard book trim sizes and what they are used for
KDP details read from kdp.amazon.com help pages on 25 September 2026. Uses are common conventions, not rules.
| Trim size | Commonly used for | Pages for 80,000 words | KDP standard | Folio print PDF |
|---|---|---|---|---|
| 5 × 8 in | Fiction, poetry, shorter nonfiction | About 320 | Yes | Yes |
| 5.5 × 8.5 in | Memoir, fiction, self-help | About 291 | Yes | Yes |
| 6 × 9 in | Trade nonfiction, business books, most paperbacks | About 267 | Yes — KDP's default | Yes |
| 7 × 10 in | Textbooks, technical and reference books | Depends on layout | Yes | Yes |
| 8 × 10 in | Workbooks, photo-led nonfiction | Depends on layout | Within KDP's custom range | Yes |
| 8.5 × 11 in (US Letter) | Workbooks, manuals, journals | Depends on layout | Yes | Yes |
| A5 and B5 | Books printed for UK and European markets | Depends on layout | Within KDP's custom range | Yes |
Trim sizes, custom-size limits, bleed, margins and page-count ranges were read from Amazon KDP's help pages on 25 September 2026. Page estimates use the stored densities in the Book Page Count Calculator — about 250 words a page at 5 × 8, 275 at 5.5 × 8.5 and 300 at 6 × 9.
Match the trim to books like yours on the shelf: most trade nonfiction is 6 × 9, much fiction is smaller, and workbooks need room to write. Then check the page count at that trim. A very thin book looks slight at 6 × 9; a very long one becomes expensive to print at 5 × 8.
Changing trim late means re-formatting the interior and redesigning the cover wrap, because the spine width follows the page count.
If any image or colour runs to the edge of the page, KDP needs a 0.125-inch bleed on the outer edges — a 6 × 9 book is then set up at 6.125 × 9.25 inches. Text-only interiors do not need bleed.
The inside margin grows with page count so text is not lost in the binding: KDP asks for at least 0.375 inch on books of 24 to 150 pages, rising to 0.875 inch at 701 to 828 pages.
Gixo Folio exports a print PDF at 5 × 8, 5.5 × 8.5, 6 × 9, 7 × 10, 8 × 10, A4, US Letter, A5 or B5, with running headers, page numbers and a table of contents. The PDF has no bleed, so it suits text interiors; books with images to the edge need a formatter that adds bleed.
Frequently Asked Questions
Formatting and publishing guides
The steps that depend on the trim you choose.
More Gixo Folio pages
Related book writing, publishing, and alternative pages.