The full KDP paperback menu
| Trim size | Typical books | Print-cost tier |
|---|---|---|
| 5″ × 8″ | Mass-market style fiction, novellas | Regular |
| 5.25″ × 8″ | Fiction, trade paperbacks | Regular |
| 5.5″ × 8.5″ | Fiction, memoir, poetry | Regular |
| 6″ × 9″ | The default: most novels & nonfiction | Regular |
| 6.14″ × 9.21″ | “Royal” size, common outside the US | Large (over 9″ tall) |
| 6.69″ × 9.61″ | “Crown quarto”, illustrated nonfiction | Large |
| 7″ × 10″ | Workbooks, children's, textbooks | Large |
| 7.44″ × 9.69″ | US comic / graphic novel size | Large |
| 7.5″ × 9.25″ | Textbooks, manuals | Large |
| 8″ × 10″ | Children's, cookbooks, photo books | Large |
| 8.25″ × 6″ | Landscape: children's, photo books | Large |
| 8.25″ × 8.25″ | Children's, gift books | Large |
| 8.5″ × 8.5″ | Children's picture books, coloring | Large |
| 8.5″ × 11″ | Workbooks, coloring, journals, textbooks | Large |
“Large trim” is KDP's pricing term, not a vibe: any book wider than 6.12″ or taller than 9″ prints on the large-trim cost table — in black ink, $0.017 per page instead of $0.012 once you're past the flat-rate page range. On a 300-page book that's $1.50 more per copy, every copy, forever. Our royalty calculator applies the right tier automatically.
What readers expect (the real deciding factor)
- Novels & memoir: 5.5×8.5 or 6×9. A novel at 8.5×11 reads as a workbook and reviews notice.
- Nonfiction / business / self-help: 6×9 is the safe standard; 7×10 for worksheet-heavy titles.
- Coloring & activity books: 8.5×11 (room to color, standard in the category) or 8.5×8.5. Yes, it's large-trim pricing — the category accepts it because every competitor pays it too.
- Children's picture books: 8.5×8.5 or 8×10 — and everything bleeds, which changes your page size (below).
- Journals & planners: 6×9 for handbags, 8.5×11 for desk planners. See low-content book specs.
- Cookbooks: 8×10 or 8.5×11 — photos need the room, and kitchens need the lay-flat presence.
What changes with the size
Page size in your file. No-bleed interiors are built at exactly trim size. With bleed, add 0.125″ to the width and 0.25″ to the height (bleed on top, bottom, and outside edge): an 8.5×11 bleed interior is 8.625×11.25. Uploading trim-size pages for a bleed book is the page-size mismatch rejection.
Margins scale with page count, not trim. The gutter grows with thickness (0.375″ at 24–150 pages up to 0.875″ at 701–828) at every size — details in the margin guide.
Spine math is size-independent — pages × paper factor (KDP) or pages ÷ PPI (Ingram) — but the cover grows with the trim. Run your numbers in the spine calculator.
Page limits apply to all sizes: black-ink paperbacks run 24–828 pages (color and hardcover ranges are shorter — premium color caps lower, hardcover is 75–550; see hardcover vs paperback).
IngramSpark's menu is wider — more sizes, true landscape options, and sizes KDP doesn't offer at all. If a book was designed for an Ingram-only size, it can't move to KDP without a re-layout. One more asymmetry in KDP vs IngramSpark.
Built your book at one size and want another? That's a re-layout, not a resize — margins, gutter, and cover all move. Send us the files and we'll run the full 13-point check and tell you in plain English what the conversion involves. The check is free. Get the free check →
The honest limit
There is no “best” trim size in the abstract — there's the size your category's buyers already trust, at a print cost your price can carry. The one genuinely wrong answer is choosing a size because your software defaulted to it: US Letter (8.5×11) documents and A4 exports are behind more first-upload rejections than any design flaw we see. Pick the size on purpose, then set your document to match it — in that order.
Or send us the files — the check is free
Email your interior and cover PDFs and we'll tell you exactly what's wrong — in plain English, free, within 48 hours. If it does need fixing, the by-hand fix is $19 and we redo it free if KDP rejects it for a formatting issue we were hired to fix. We rebuild files to be compliant with KDP's published spec — that's the promise we can keep.