Print book formatter
Upload a .docx and get a print-ready interior PDF — your trim size, mirrored margins, and an inside margin sized to the finished page count. Free to try; $5 to unlock a file.
The part most tools get wrong
A print interior is not a PDF with a page size. The inside margin sits against the spine, so it has to swap sides on every page — and it has to be wider than the outside margin, because a bound book curves away from you near the binding.
How much wider depends on how thick the book is. KDP requires 0.375 inches up to 150 pages, rising to 0.875 inches past 700. So the margin depends on the page count, and the page count depends on the margin. We render once to measure, then again with the right geometry.
What you get back
- Your exact trim size — the PDF page is the finished book page, no scaling at the printer.
- Mirrored margins, inside edge alternating correctly across the spread.
- A gutter sized to your page count, to KDP's published minimums.
- Chapters opening on right-hand pages, as printed books do.
- Justified serif text with hyphenation, and no single lines stranded across a page turn.
- Embedded fonts, so the printer renders exactly what you saw.
Order a proof before a full run
We build to KDP's published specification and check the geometry on every file, but print is unforgiving and a screen is not paper. A proof copy costs a few dollars and is the only way to be certain about margins, spine drift, and how the type actually sits on the page. Do that once before ordering a hundred.
Questions
- What is a gutter, and why does it depend on page count?
- The gutter is the inside margin, next to the spine. A thicker book curves more near the binding, so more of the inside edge becomes hard to read — which is why KDP requires a larger inside margin as page count grows. We count your finished pages and apply the right one automatically.
- What are mirrored margins?
- The inside margin has to be on the left of a right-hand page and the right of a left-hand page, because the spine alternates sides. Getting this wrong is the most common reason a first proof looks wrong: text drifts toward the spine on every other page.
- Which trim size should I pick?
- 6\u00d7\u0039\u2033 is the default for most novels and non-fiction. 5\u00d78\u2033 and 5.5\u00d78.5\u2033 suit shorter books and feel more like a mass-market paperback. Pick the one you selected on KDP — changing it later changes your page count.
- Do I need bleed?
- Only if something is meant to run off the edge of the page — a full-bleed image or a coloured background. A text interior does not, which is the usual case for novels, so we produce a no-bleed file.
- Will this pass KDP's checks?
- The geometry is built to KDP's published requirements: standard trim sizes, their minimum inside margin for your page count, and embedded fonts. We would still order one proof copy before a full run — see the note below.
- What does it cost?
- Formatting is free. Free files include a small footer line, allow three adjustments, and are kept for 24 hours. Unlocking one file costs $5 once — no subscription — which removes the line, lifts the adjustment limit, and keeps the file for 30 days.
Doing the ebook too? Use the Kindle formatter or the EPUB formatter.