Know before you upload.
Free tools that check a book file against Amazon KDP's published requirements and show what needs fixing before you upload.
Torcul also makes the files. From a Word or Markdown manuscript it produces a print-ready interior, an EPUB that passes EPUBCheck and a cover sized to the final page count. You see every page before you pay.
Free tools
No account and no limits.
Print PDF checker
Trim size, bleed, fonts and color, then widows and orphans, page by page.
Cover size checker
Whether a full cover fits the interior, and if not, why.
EPUB accessibility checker
The accessibility metadata the EU requires, and whether the file backs it up.
Margin & gutter calculator
KDP's minimum margins, and the wider ones a well-made book uses.
Spine & cover size
Spine width, full artwork size and fold positions, from page count and paper.
Structure review
The chapter structure read from a .docx, with the evidence for each heading.
Guides
Why KDP rejected your interior
Nine causes, and how to spot each one before upload.
How KDP gutter margins work
The minimum depends on the page count, which depends on the margins. How to settle it.
EPUB accessibility & the EU Act
The five properties an ebook must declare since June 2025, and why a false claim is worse than none.
Comparisons
Vellum alternatives for Windows
Vellum is macOS only. The alternatives, and what each one gives up.
Atticus compared
Its strengths, what its users report, and the two cases where it is the better choice.
What formatting a book costs
A formatter, a licence or Torcul, in money and time — including the costs nobody lists.
Questions
Does Torcul run on Windows?
Yes. It runs in a browser, on Windows, macOS or Linux. Nothing is installed.
Which manuscript files can I use?
A Word document (.docx) or a Markdown file. A Google Doc can be downloaded as a .docx first; From Google Docs to a KDP paperback shows how.
Which languages can a book be in?
English, German, French, Spanish, Italian, Portuguese, Dutch and Turkish.
KDP does not list Turkish among the languages it publishes. A Turkish book is still made to KDP's measurements, but nothing says KDP will take it.
Which trim sizes can Torcul set?
Eight paperback sizes, in inches: 5 × 8, 5.06 × 7.81, 5.25 × 8, 5.5 × 8.5, 6 × 9, 6.14 × 9.21, 6.69 × 9.61 and 7 × 10. The free calculators cover all sixteen of KDP's sizes.
Can it make a hardcover?
No. The interior and the cover are made for a paperback. KDP has its own rules for a hardcover's page count and cover.
Does Torcul write or rewrite my text?
No. It lays out the text you wrote, and does not generate or rewrite it.