Book Interior Formatter
Paste or upload your manuscript (Word .docx, Markdown or text) and get a print-ready paperback interior PDF. Choose the trim size, margins with an automatic gutter for your page count, font and spacing, chapter openings on right-hand pages, running headers and page numbers, and check every spread in the live preview.
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How to use the Book Interior Formatter
- Add your manuscript: paste it into the box (start each chapter with
# Title) or upload a .docx, .md or .txt file. Word Heading 1 or Title paragraphs start chapters. - Enter the book details: title, subtitle and author for the title page and headers, plus your copyright text.
- Pick the trim size your printer offers, such as 6 × 9 in, and keep Auto gutter on so the inside margin grows with the page count.
- Adjust the text and chapter options and page through the spread preview until it looks right.
- Press Create print-ready PDF and upload the file as your paperback interior.
Common trim sizes and suggested settings
| Trim size | Typical use | Body text | Outside / top / bottom |
|---|---|---|---|
| 5 × 8 in | Novels, poetry, compact paperbacks | 10–11 pt | 0.5 in / 0.6 in / 0.6 in |
| 5.25 × 8 in, 5.5 × 8.5 in | Fiction, memoir | 10.5–11.5 pt | 0.5 in / 0.7 in / 0.7 in |
| 6 × 9 in | The most common trade paperback size for fiction and non-fiction | 11–12 pt | 0.5–0.75 in / 0.75 in / 0.75 in |
| 7 × 10 in | Workbooks, textbooks, cookbooks | 11–12 pt | 0.6 in / 0.75 in / 0.75 in |
| 8.5 × 11 in | Manuals, large-print and workbooks | 12–14 pt | 0.75 in / 0.75 in / 0.75 in |
These are starting points rather than rules; always check the trim sizes and minimum margins your printer lists.
Anatomy of a book interior
- Recto and verso: page 1 is a right-hand (recto) page, so odd pages are on the right and even pages on the left. The binding is on the left of recto pages and on the right of verso pages.
- Front matter: the title page (recto), copyright page (its back, verso), optional dedication and the table of contents. These pages carry no running headers or page numbers.
- Chapter openers: each chapter begins lower on the page (the chapter drop) without a running header, and the first paragraph is not indented.
- Running headers: traditionally the author's name on left pages and the book title on right pages, or the title and current chapter.
- Widows and orphans: a single line of a paragraph stranded at the top or bottom of a page. The formatter moves lines between pages to avoid them.
Preparing the manuscript text
| You type | In the book |
|---|---|
# The Light on the Hill | New chapter (on a right-hand page) with this title |
## The harbor office | Subheading inside a chapter |
*italic*, **bold** | italic, bold |
*** on its own line | Centred scene break |
> quoted text | Indented block quotation |
- item or 1. item | Bulleted or numbered list item |
| Blank line | New paragraph |
Frequently asked questions
What margins does a 6 × 9 paperback need?
Print-on-demand services use a larger inside (gutter) margin for thicker books because pages curve into the spine. A widely used guide (Amazon KDP's, for books without bleed) is: 24–150 pages 0.375 in, 151–300 pages 0.5 in, 301–500 pages 0.625 in, 501–700 pages 0.75 in and 701–828 pages 0.875 in, with at least 0.25 in on the outside, top and bottom. Many designers use 0.5–0.75 in outside margins for a more comfortable page. Auto gutter applies the table above after counting your pages.
What is the gutter in book formatting?
The gutter is the inside margin, next to the binding. On right-hand (odd, recto) pages it is the left margin and on left-hand (even, verso) pages it is the right margin, so the tool mirrors the margins from page to page.
Why do chapters start on right-hand pages?
It is a traditional book convention: a reader turning the page meets the new chapter on the right. When a chapter would otherwise start on a left page, a blank page is inserted. Turn the option off to save pages; chapters then start on the next page.
Which fonts can I use?
The PDF uses the standard PDF fonts Times, Helvetica and Courier, which every printer accepts. They cover English and Western European accented letters; characters outside that set (for example Cyrillic, Greek, Asian scripts or emoji) appear as question marks and a warning is shown. Some printers ask for all fonts to be embedded; check your printer's requirements and, if needed, re-save the PDF with embedded fonts in a desktop PDF tool.
Does the file meet my printer's requirements?
The PDF is sized exactly to the trim size, uses black text, has no bleed and has an even number of pages, which suits typical text-only paperback interiors. Every printer has its own checks, so always review the printer's online previewer or proof copy before ordering copies.
How do I format my Word document for this tool?
Apply the Heading 1 (or Title) style to each chapter title and leave the body text in Normal style. Bold and italic are kept, Heading 2 becomes a subheading, centred lines stay centred and a paragraph containing only *** becomes a scene break. Images, footnotes and tables are not included.
How many pages will my book have?
It depends on trim size, font size, spacing and margins; the page count updates live in the preview. As a rough guide, a 6 × 9 in book in 11 pt Times with 1.4 line spacing holds roughly 300–400 words per full page, depending on paragraph and dialogue length.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.