Questions
The whole thing rests on people believing the privacy claim, and that only works if the explanations stand up. If something here reads as evasive, it needs rewriting.
Is my book uploaded anywhere?
No. The converter is JavaScript running in your browser. It reads the file off your own disk and never sends it anywhere. Don't take our word for it: open devtools, watch the Network tab, and convert something. Nothing goes out.
Why would I want a PDF instead of an EPUB?
Because you want to print it, annotate it in an app that only takes PDFs, hand it to someone whose device won't open an EPUB, or keep a copy whose pages don't move. An EPUB reflows by design, which is exactly right for reading and exactly wrong when the page numbers have to stay put.
Will it work on a book I bought from Amazon or Kobo?
Only if it's DRM-free. Most shop-bought books are encrypted, and we don't remove DRM. We detect it and tell you, rather than handing you three hundred pages of noise. Books from Standard Ebooks, Project Gutenberg, itch.io, most publishers' direct stores and every StoryBundle are DRM-free and convert fine.
How good does it look?
Good on ordinary prose. Novels, essays, manuals and reports come out properly typeset: justified text, real chapter breaks, a contents page with working page numbers, running heads and PDF bookmarks. It is weaker on anything that depends on layout: tables get flattened to their text, and a fixed-layout comic is really just its own pictures again.
What about books that are not in English?
Anything in the Latin alphabet is fine, accents included: French, German, Spanish, Polish, Turkish, Vietnamese and so on. Greek, Cyrillic, Hebrew, Arabic and the CJK scripts are not, because we use the fonts already built into every PDF reader and those fonts do not contain those characters. We check before you convert and tell you.
Why is the PDF smaller than the EPUB was?
Usually because it carries no fonts. We set the text in the standard PDF fonts, which live inside your PDF reader rather than inside the file. Where an EPUB was mostly pictures, the PDF will be about the same size, because the pictures are still pictures.
Is there a file size limit?
Around 200 MB in practice. The whole book sits in your browser tab while it converts, so a big illustrated one can run the tab out of memory. Most books are a few megabytes, so this rarely comes up.
Do you keep the converted PDF?
We've got nowhere to keep it. The file is assembled in memory and handed to your browser as a download. Close the tab and it's gone.
Does it work offline?
Yes, once the page has loaded. Pull the plug and convert away. It never needed the network in the first place.
Can I convert a book I do not own?
That's between you and whoever holds the copyright. We're a format converter and we never see your file, but converting something you have no right to copy is still infringement. Stick to what you're entitled to.
Wondering how it manages all this in a browser?
Have a read →