Trim size is one of the first decisions in preparing a print book, and one of the hardest to change later. It affects how the book feels in the hand, how it looks next to similar books, how many pages it runs to, and how much each copy costs to print. This guide walks through the common sizes, what each suits, and how to decide.
The common trim sizes
| Trim (inches) | Feel | Typical use |
|---|---|---|
| 5 x 8 | Compact, easy to hold | Fiction, poetry, novellas, devotionals |
| 5.5 x 8.5 | Classic trade paperback | Fiction, memoir, Christian living, self-help |
| 6 x 9 | The workhorse | Non-fiction, business, history, longer novels |
| 7 x 10 | Roomy | Textbooks, technical books, illustrated non-fiction |
| 8.5 x 11 | Letter size | Workbooks, journals, manuals, large-format guides |
These five are also the sizes BooksOasis prints. Other platforms offer more, including square formats for children's and photo books, but these cover the great majority of self-published books.
Trim sizes by genre
| Genre | Usual sizes | Why |
|---|---|---|
| Literary and general fiction | 5.5x8.5, 6x9 | Trade paperback look |
| Genre fiction (romance, thriller, fantasy) | 5x8, 5.5x8.5, 6x9 | Matches shelf neighbours; long fantasy often 6x9 to control page count |
| Poetry | 5x8, 5.5x8.5, 6x9 | Short lines suit narrower pages |
| Memoir and biography | 5.5x8.5, 6x9 | Readable, room for photos |
| Business and self-help | 5.5x8.5, 6x9 | Standard non-fiction look |
| History and reference | 6x9, 7x10 | Long texts, maps and notes |
| Devotionals | 5x8, 5.5x8.5 | Hand-held daily reading, often a gift |
| Workbooks and journals | 8.5x11, 7x10 | Space to write |
| Textbooks and manuals | 7x10, 8.5x11 | Diagrams, tables, wide layouts |
These are typical patterns, not rules. The quickest check is to look at the top-selling books in your exact category and note their dimensions, usually listed in the product details.
How trim size changes page count
A bigger page holds more words, so the same manuscript runs to fewer pages. Exact numbers depend on font, size, margins and spacing, but the pattern is reliable.
As a rough picture, an 80,000-word novel set at 5x8 runs noticeably longer than the same text at 5.5x8.5, and 6x9 is shorter still. Moving from 5x8 to 6x9 often cuts the page count by a fifth or more at similar type settings.
Rather than guess, set a few sample chapters at each size in your layout tool and multiply out. It takes ten minutes and gives you real numbers for your book.
How trim size changes printing cost
On print on demand, black-ink costs rise with page count. On KDP (Amazon.com), a regular-trim paperback costs $1.00 plus $0.012 per page from 110 to 828 pages. So every 100 pages you save is $1.20 off every copy.
But size has a threshold. KDP treats trims wider than 6.12 inches or taller than 9 inches as large trims, which cost $1.00 plus $0.017 per page instead.
| Black-ink paperback on KDP | 300 pages | 400 pages |
|---|---|---|
| Regular trim (up to 6.12 x 9) | $4.60 | $5.80 |
| Large trim (for example 7x10, 8.5x11) | $6.10 | $7.80 |
From KDP's printing cost help page. See print on demand costs for the full tables.
That's why 6x9 is so popular: it's the largest common size that stays a regular trim on KDP, so it gives the most words per page at the lower per-page rate.
A worked example
Suppose a long fantasy novel sets at 560 pages in 5.5x8.5 and at about 460 pages in 6x9. On KDP:
| Trim | Pages | Printing cost | Royalty at $17.99 (60%) |
|---|---|---|---|
| 5.5 x 8.5 | 560 | $7.72 | $3.07 |
| 6 x 9 | 460 | $6.52 | $4.27 |
Example calculations with assumed page counts: printing = $1.00 + $0.012 × pages; royalty = 60% of list − printing.
Over 1,000 copies, the larger trim is worth about $1,200 more, simply from fewer pages. The book also feels less daunting to readers, and ships lighter.
Beyond cost: how the book feels
- Hand feel. 5x8 and 5.5x8.5 books are easy to carry and read in bed; 6x9 feels more substantial.
- Line length. Very wide pages with small type are tiring to read; wider trims need suitable margins and font size. See book print margins.
- Thickness. A 600-page 5x8 book can feel like a brick; the same text in 6x9 is slimmer.
- Shelf presence. A book much larger or smaller than its neighbours can look out of place.
- Images. Photos, charts and maps need room; 7x10 or 8.5x11 may suit illustrated non-fiction.
Bleed: when images run to the edge
If any image or color block runs right to the edge of the page, the file needs bleed: a small extra margin beyond the trim that gets cut off, so no white sliver appears. Most platforms want about 0.125 inches of bleed on the outside edges, and a page file slightly larger than the trim size. Text-only novels don't need bleed at all. Check each platform's help page for exact file dimensions before exporting.
Large-print editions
A large-print edition, typically set in 16 to 18 point type, is a thoughtful way to reach older readers and readers with low vision, and devotionals and inspirational books often do well in it. Large type means many more pages, so a bigger trim such as 6x9 helps keep the book manageable. Publish it as a separate edition with its own title page line ("Large Print Edition") so readers can find it.
Children's and picture books
Picture books often use square or landscape formats, such as 8.5x8.5 or 8.25x8.25, which some platforms offer and others don't. Chapter books for older children usually follow fiction sizes like 5.5x8.5. If you plan a picture book, check which platforms print your preferred shape before illustrating, since artwork is drawn to a specific ratio.
Ebooks don't have a trim size
Ebooks reflow to fit each reader's screen, so trim size only matters for print. Keep your print layout decisions (page breaks, drop caps, headers) separate from your ebook file. An EPUB made from a print-ready PDF usually reads poorly; start the ebook from your manuscript instead. See how to format an ebook from Word.
Paperback and hardcover sizes
Many authors use the same trim for paperback and hardcover, which keeps the interior file nearly identical. Others choose a slightly larger hardcover for a premium feel. Either way, each format needs its own cover built from the platform's template for that size and page count, since hardcover wraps and spines differ from paperback covers. See paperback vs hardcover profit.
Series consistency
For a series, pick one trim and keep it for every volume. Matching sizes and spine designs make the books look like a set on a reader's shelf, and readers who collect a series notice when one volume is taller than the others. Decide on the series trim with the longest planned book in mind, since changing later means re-issuing earlier volumes.
If you print in more than one place
Many authors print on KDP for Amazon and elsewhere for everything else. Using a size every platform offers, such as 5x8, 5.5x8.5 or 6x9, means one interior file works everywhere and only the cover changes per platform.
Choosing your trim in five steps
- Check your category.Note the sizes of the top-selling books in your genre.
- Set sample pages.Typeset a few chapters at two or three sizes.
- Estimate page count and cost.Multiply out, and check the large-trim threshold.
- Check platform support.Make sure every platform you'll print with offers that size.
- Order a proof.Hold the book before you commit, and read a few pages the way a reader would.
Trim sizes on BooksOasis
BooksOasis prints paperbacks and hardcovers on demand in five trims: 5x8, 5.5x8.5, 6x9, 7x10 and 8.5x11 inches. Paperbacks can run from 32 to 800 pages and hardcovers from 24 to 800. When you add a page count and trim size to an edition, the publisher dashboard quotes its printing cost and your minimum price (that cost plus 30%). Everything above the minimum is yours, and the reader pays shipping.
Because these five sizes are also standard elsewhere, a book formatted for 5x8, 5.5x8.5 or 6x9 on another platform usually needs only its cover rebuilt from the BooksOasis template for its page count.
What BooksOasis does not do
- It doesn't offer square or unusual trims such as 8.5x8.5.
- It doesn't distribute print books to other retailers.
- Its plans cost a flat yearly fee whether or not you sell.
Common mistakes
- Choosing an unusual size that not every platform supports, forcing different editions.
- Going just past 6.12 inches and paying large-trim rates for little benefit.
- Squeezing text into a small trim with tiny type and narrow margins to save pages.
- Changing trim mid-series, so the books no longer match.
- Reusing a cover made for a different size or page count, which leaves the spine text off-centre or the artwork cropped.
Sources
Checked September 2026: KDP printing cost; KDP print options; KDP trim size, bleed and margins.
In short
Pick the size readers expect in your genre, then use page count and cost to decide between close options. 6x9 gives the most words per page while staying a regular trim on KDP, 5x8 and 5.5x8.5 suit compact fiction and devotionals, and 7x10 or 8.5x11 suit workbooks and illustrated books. Keep one size across a series, check every platform supports it, and hold a proof before you commit.
Questions
What is a trim size?
The finished page size of a printed book, width by height, after the pages are cut. For example, 6x9 means 6 inches wide and 9 inches tall.
What is the most common trim size for self-published books?
6x9 inches is the most common for non-fiction and many novels. 5x8 and 5.5x8.5 are popular for fiction.
What size should a novel be?
Most novels use 5x8, 5.5x8.5 or 6x9. Smaller sizes feel like classic paperbacks; 6x9 fits more words per page and lowers page count.
What size is best for non-fiction?
6x9 is the standard for most non-fiction. Workbooks and textbooks often use 7x10 or 8.5x11 for room to write and for diagrams.
Does trim size affect printing cost?
Yes, in two ways. Larger pages hold more words, so the book has fewer pages. And on KDP, trims wider than 6.12 inches or taller than 9 inches count as large trims, which cost more per page.
Can I change trim size after publishing?
Usually you need a new interior and cover for the new size, and on many platforms a new edition. Choose carefully before your first print run.
What trim sizes does BooksOasis print?
5x8, 5.5x8.5, 6x9, 7x10 and 8.5x11 inches, for paperbacks (32 to 800 pages) and hardcovers (24 to 800 pages).
Should my paperback and hardcover be the same size?
Often yes, for consistency, but not always. Some authors publish a 5.5x8.5 paperback and a 6x9 hardcover. Check each size's cover template.
Does trim size affect the spine width?
Indirectly. Spine width depends on page count and paper, and trim size changes the page count.
Should I match other books in my genre?
Usually. Readers and bookshops expect certain sizes for certain genres, and a book that matches looks right on the shelf and online.
What is bleed?
Extra image area beyond the trim, usually about 0.125 inches, which is cut off when the book is trimmed. You need it only if images or color run to the edge of the page.
What size is best for a large-print edition?
A larger trim such as 6x9 helps, because 16 to 18 point type adds many pages. Publish it as a separate edition labelled Large Print.
Is 6x9 a large trim on KDP?
No. KDP counts trims wider than 6.12 inches or taller than 9 inches as large, so 6x9 stays at the regular per-page printing rate.
Publish your paperback and hardcover
Five trim sizes, printed on demand, from $29.99 a year.