Where to find EPUBs that will actually convert

The commonest reason a conversion fails has nothing to do with the converter. The file is locked, and it was locked at the moment you bought it.

That’s worth understanding before you go looking for a better tool, because no tool fixes it. What does fix it is buying from somewhere that sells you the file rather than a licence to read it, and there are more of those than most people realise.

How to tell what you’ve got

An EPUB is a zip archive. Rename a copy from book.epub to book.zip, open it, and look at the META-INF folder.

• A file called encryption.xml or rights.xml means DRM. The book won’t convert here and won’t open in Calibre either.
• Neither of those, and you have a plain EPUB that will convert.

A file ending .acsm isn’t a book at all. It’s a few hundred bytes of Adobe download token that Adobe Digital Editions exchanges for the real file, and the real file comes back locked. If that’s what you downloaded, you don’t have the book yet.

The converter runs the same check before it starts, so you can also just drop the file in and read what it says. Nothing is uploaded either way. Why some EPUBs can’t be converted goes through the failure modes in more detail.

Public domain, properly made

Standard Ebooks is the one to know about. Volunteers take public-domain texts and typeset them properly: real hyphens where hyphens belong, proper em dashes, consistent quotation marks, a sane table of contents, a cover that isn’t a scan of a paperback. Free, no account, DRM-free by definition, and the EPUBs are cleaner than most things you can buy. If a book you want is on there, use that version.

Project Gutenberg has the volume, at over 70,000 titles. The quality varies because much of it was transcribed decades ago, so formatting can be plain and occasionally rough. Still the first place to look for anything out of copyright.

The Internet Archive and Open Library hold an enormous amount, some of it public domain and freely downloadable, some of it lending copies that carry DRM. Check which you’ve got before assuming.

Wikisource exports EPUBs of anything it hosts, which includes a lot of primary sources, out-of-copyright non-fiction and government documents you’d struggle to find elsewhere.

Public-domain books convert particularly well, incidentally. They’re mostly plain prose with no illustrations and no unusual layout, which is exactly what this converter is good at.

Shops that sell you the file

Technical publishers are the most reliable category. No Starch Press, the Pragmatic Bookshelf, Manning and O’Reilly all sell DRM-free ebooks direct, usually in several formats at once, and usually with free updates when the book is revised. Programmers complained loudly enough for long enough that the whole sector gave up on locking files.

Leanpub works the same way, mostly for self-published technical writing, and gives you EPUB and PDF together.

Some literary publishers sell direct and unlocked. Verso and Tor have both done so for years. It’s worth checking a publisher’s own shop before defaulting to a big retailer, because the version they sell you is often the one without the lock.

Humble Bundle runs book bundles regularly. They’re DRM-free, they’re cheap, and they’re a good way to end up with forty technical books you’ll convert three of.

itch.io has grown a serious independent publishing corner, particularly for tabletop games, zines and small-press fiction. DRM-free throughout.

Author websites. Plenty of writers sell straight from their own site, and when they do it’s almost always an unlocked file. It also gives them a much larger cut than a retailer would.

The big retailers

Books bought from Amazon, Apple Books, Google Play Books, Kobo and Barnes & Noble generally carry DRM. Some publishers opt out and some titles arrive unlocked, so it’s not universal, but it’s the default and you can’t usually tell before buying.

If that matters to you, the practical answer is to check whether the same book is available from the publisher direct, or from one of the shops above, before buying it from a retailer. Frequently it is, at the same price.

Library borrowing through Libby or OverDrive is always DRM-protected. That’s the mechanism by which the loan expires, so there’s no version of library lending that produces a convertible file.

Books you made yourself

Easy to forget. If you write, an EPUB exported from Scrivener, Vellum, Pages, Word, Google Docs or Pandoc has no DRM on it, and converting your own manuscript to a PDF at 6×9in is a fast way to see what it’ll look like as a paperback. Proofreading on paper catches things a screen doesn’t.

Same for anything you’ve saved with a read-later tool, or generated from a website with a browser extension, or downloaded from a documentation site that offers an EPUB build. All of it converts.

What about the lock on a book I’ve paid for?

This site doesn’t help with that and won’t. The tool refuses DRM-protected files by design, it isn’t an oversight, and there’s nothing to configure. Whether you’re entitled to strip a lock from a book you’ve bought depends on where you live, and it’s a question about your jurisdiction rather than about file formats.

The one thing worth saying is that the situation is avoidable going forward. Every source on this page sells or gives you a file you own, and the catalogue between them is much larger than it looks from inside a retailer’s app.

Once you’ve got a file

Drop it into the converter. If it’s clean, you’ll get a page estimate and a set of options; if it’s locked, you’ll get told which of the two schemes it found before anything else happens.

Then it’s a question of what you’re converting it for, which is mostly about page size: choosing a page size and margins for the general case, printing a booklet if you want a folded object at the end of it.