MOBI to PDF

A Kindle book is reflowable: the text fills whatever screen it is on, at whatever size the reader chooses. A PDF has fixed pages laid out for one size of paper.

Converting one to the other throws away the property that makes it readable on a phone. There are good reasons to do it anyway — printing, a submission system that only takes PDF, a device with no ebook reader — and this does it cleanly. Just be sure that is what you want.

A book bought from Amazon is encrypted to the account it was bought for. That is the point of it, and no converter can read one — a page claiming otherwise is either lying or circumventing the protection, and neither is something this site does.

The check is explicit: an encrypted book is refused with a plain explanation rather than converted into a file of garbage.

Books without DRM convert normally, and there are more of them than people expect: Project Gutenberg, Standard Ebooks, most publishers selling direct, Humble Bundle, anything you produced yourself, and anything already in Calibre.

A Kindle book is compressed HTML, so the text and its heading structure come back cleanly. Chapters, paragraphs and emphasis-by-structure survive.

Images, cover art, footnotes, tables and the book's own styling do not. Those live in separate records with their own indexes, and reassembling them faithfully is a much larger job than reading the text — which is the part you read.

PDF has fourteen built-in fonts that every reader already has, and they cover WinAnsi — Latin letters, accented European characters, curly quotes, the euro and pound signs. Nothing else.

Writing Chinese, Japanese, Korean, Arabic, Hebrew, Thai, Devanagari or Cyrillic means embedding a font that contains those glyphs, and a font with usable CJK coverage is several megabytes. Downloading that on the chance a visitor needs it is not a reasonable trade for a page that mostly converts English.

So instead of producing a document full of blank boxes, unencodable characters become a question mark and the conversion tells you exactly how many were affected and which script they belonged to. If your text is in one of those scripts, this is the wrong tool and you should use a desktop converter — that is a more useful answer than a broken file.