Quick Answer
Use mirror margins, set the inside gutter wider than the outside margin, and add bleed only if images or colour reach the page edge. Most text-only novels do not need bleed. Most print interiors need at least 0.75 inches inside gutter and 0.5 inches outside/top/bottom.
What Bleed, Gutter and Margins Look Like
Blue dashed line: safe text area. Red dashed line: bleed edge. The wider inside space is the gutter.
Margin & Gutter Chooser
Use this as a starting point. Always check your platform's final proof before approving the book.
Header, Gutter, Bleed: Quick Definitions
Header is the small running text at the top of a page, often the book title, author name, chapter title, or section title. It sits inside the margin, not in the bleed.
Gutter is the inside margin closest to the spine. A 500-page book needs a wider gutter than a 120-page book because the pages curve into the binding.
Bleed is the part of a design that extends past the final trim line so the printer can cut the page cleanly. If your pages are only text on white paper, you probably do not need bleed.
Recommended Book Margins
| Page count | Inside gutter | Outside / top / bottom | Best for |
|---|---|---|---|
| 24-150 pages | 0.625-0.75 in | 0.5 in | Short fiction, poetry, lead magnets |
| 151-400 pages | 0.75-0.875 in | 0.5-0.625 in | Most novels and nonfiction |
| 401+ pages | 0.875-1.0 in | 0.625 in | Long fantasy, textbooks, reference |
Do You Need Bleed?
You need bleed if images, background colour, illustrations, maps, charts, or design elements touch the edge of the page. Add 0.125 inches on every side. A 6 x 9 inch page with bleed becomes 6.25 x 9.25 inches in the PDF file.
You do not need bleed if your book is text-only and nothing touches the edge. Most novels, memoirs, business books, and standard nonfiction books are no-bleed interiors.
Common Formatting Mistakes
- Using the same inside and outside margin on a thick book.
- Forgetting mirror margins, so the gutter appears on the wrong side of every second page.
- Adding bleed to a text-only book and then placing page numbers too close to the trim line.
- Exporting facing-page spreads instead of single pages.
- Putting headers on blank pages, title pages, or chapter opening pages.
Books.by Compatibility
Books.by accepts standard print-ready PDF interiors. If your file is correctly prepared for KDP or IngramSpark - right trim size, embedded fonts, single pages, correct margins - you can usually use the same file on Books.by and add a direct-sales channel without reformatting.
Next Steps
Use the complete print formatting guide for the full file-preparation workflow. Then choose your fiction book size, estimate page count with the word count to pages calculator, and compare royalties with the KDP cost calculator.
