📋 Table of Contents
📏 KDP Trim Size Comparison Tool
Filter by book type, then click any size to see full details — genre fit, page count estimate, gutter requirements, cost rating, and hardcover availability.
Why Trim Size Is One of the Most Important Publishing Decisions You’ll Make
Most first-time KDP authors choose a trim size without much thought, often defaulting to whatever their word processor’s default page size happens to be. That is usually 8.5×11 inches — a letter-sized document that produces a book that looks and feels like a photocopied office report. It is also one of the most expensive trim sizes to print.
Trim size affects four things directly: printing cost per copy (larger pages cost more), page count (larger pages mean fewer pages from the same word count), spine width (fewer pages means a narrower spine), and reader expectations (each genre has conventions that readers recognize unconsciously and respond to).
You Cannot Change Trim Size After Publishing
Once your KDP paperback or hardcover listing is created, the trim size is permanently locked. If you need a different size later, you must create an entirely new KDP title with a new ISBN and reformat your manuscript from scratch. Choose your trim size before you begin formatting.
Best KDP Trim Sizes for Fiction
Fiction readers are among the most attuned to book format conventions. A thriller that arrives in an 8.5×11 format feels wrong immediately — not because of any rule, but because readers have handled thousands of paperbacks and have a physical sense of what a novel should feel like.
5″ × 8″ — The Fiction Standard
This is the trim size you see on most mass-market and trade paperback novels. It feels substantial even at lower page counts, holds text comfortably, and has the narrowest price point of any standard novel trim size. For romance, thriller, mystery, fantasy, and sci-fi, this is the default recommendation.
5.5″ × 8.5″ — Slightly More Space
Popular for literary fiction, general fiction, and longer novels where slightly more text per page reduces the printing cost on high page-count books. The larger text area means fewer pages from the same word count, which lowers your per-copy printing cost on books over 350 pages.
Book Formatting for KDP Guide
A complete formatting reference covering trim size conventions by genre, margin and gutter setups, font recommendations, and the full PDF export process for Word and Scrivener.
Best KDP Trim Sizes for Non-Fiction
Non-fiction has more flexibility in trim size than fiction because readers are buying for information, not for the reading experience itself. That said, there are still strong conventions — and choosing the wrong size signals that you are unfamiliar with your market.
6″ × 9″ — The Non-Fiction Workhorse
This is the single most popular trim size on KDP across all categories. Business books, self-help, health, productivity, finance, memoir, biography, parenting, and most how-to books all live comfortably at 6×9. It is the size readers expect when they pick up a “serious” non-fiction book, and it has a professional authority that smaller sizes can lack.
7″ × 10″ — Large Format Non-Fiction
Textbooks, academic books, course materials, and illustrated guides benefit from the extra page area. More space per page means more room for sidebars, callouts, illustrations, and structured layouts. The printing cost is higher, but for premium-priced educational content, the format matches the price point.
6×9 at a 50,000-Word Count Produces ~200 Pages
A 50,000-word non-fiction book at 6×9 with standard formatting (11pt Garamond, 1.25× spacing, 0.75″ margins) produces roughly 200–220 pages. That is a solid, professional-feeling trade paperback. The same word count at 5×8 would produce approximately 240–260 pages, and at 8.5×11 roughly 120–140 pages.
Journals, Workbooks, Children’s Books & Large Format
8.5″ × 11″ — Journals, Planners & Workbooks
Full letter-size pages give maximum writing and workspace. This is the standard for daily planners, habit trackers, lined journals, activity books, and course workbooks. The printing cost is the highest of any standard trim size, but buyers of planners and workbooks expect and accept a higher price point.
6″ × 9″ — Compact Journals
For more portable journals and dot-grid notebooks, 6×9 is the better option. It feels more like a personal notebook than an office document, and it carries a lower printing cost than the 8.5×11 format.
8″ × 10″ and 8.5″ × 8.5″ — Children’s Books
Picture books, illustrated children’s stories, and coloring books use landscape-oriented or square trim sizes. The 8×10 format allows large illustrations on each spread while remaining a comfortable size for a child to hold. The square 8.5×8.5 format works well for picture books where the illustration is the main content on each page.
KDP Self-Publishing Income Guide
Trim size affects your royalty directly through printing cost. This guide covers pricing strategy, royalty optimization, and how to set prices that maximize income across different trim sizes and page counts.
How Trim Size Affects KDP Printing Cost & Royalties
KDP’s printing cost per copy is calculated based on page count and page dimensions. Larger pages cost more per copy — and because larger pages fit fewer words per page, a larger trim size can actually increase your total page count compared to a smaller size with the same word count.
| Trim Size | ~Pages per 50k Words | Print Cost Range | Royalty at $12.99 |
|---|---|---|---|
| 5″ × 8″ | ~250 pages | ~$3.45 | ~$5.59 |
| 5.5″ × 8.5″ | ~220 pages | ~$3.25 | ~$5.79 |
| 6″ × 9″ | ~200 pages | ~$3.15 | ~$5.89 |
| 7″ × 10″ | ~160 pages | ~$3.55 | ~$5.49 |
| 8.5″ × 11″ | ~130 pages | ~$4.45 | ~$4.59 |
| 8″ × 10″ | ~145 pages | ~$3.95 | ~$5.09 |
* Estimates based on 11pt serif font, 1.25× spacing, standard margins. Actual costs vary. Use our Printing Cost Calculator for exact figures.
💰 Calculate Your Exact Royalty by Trim Size
Use our free tools to calculate the exact printing cost and royalty for your specific page count and pricing at any trim size.
KDP Hardcover Trim Sizes
KDP hardcover is available in a more limited range of trim sizes compared to paperback. Not every paperback size has a hardcover equivalent. If you plan to publish both formats, choose a trim size that is supported for both before you start formatting.
| Trim Size | Hardcover Available? | Notes |
|---|---|---|
| 5″ × 8″ | ✅ Yes | Standard fiction hardcover |
| 5.5″ × 8.5″ | ✅ Yes | Popular for literary fiction |
| 6″ × 9″ | ✅ Yes | Most popular non-fiction HC size |
| 6.14″ × 9.21″ | ✅ Yes | Hardcover-specific size |
| 7″ × 10″ | ✅ Yes | Large format non-fiction |
| 8.5″ × 11″ | ❌ No | Paperback only |
| 8″ × 10″ | ❌ No | Paperback only |
| 8.5″ × 8.5″ | ❌ No | Paperback only |