calibreIn previous installments of this guide, I’ve discussed using email to send e-books and files directly to your Kindle, or using a USB cable to copy e-books over from your computer. Now it’s time to look at using Calibre, a free, powerful, and not terribly user-friendly e-book library management tool to copy your files to your Kindle, and manage the files you already have on it.

Calibre isn’t for everyone, and many ordinary users will be content to use the email or drag-and-drop copying methods discussed above. (Indeed, most ordinary users will probably continue to be happy just buying e-books from Amazon and nowhere else so they don’t have to deal with sideloading at all.) But learning how to use Calibre isn’t as hard as it looks at first glance, and it can be a powerful tool for managing e-book titles on your Kindle without having to go through your Kindle’s on-board menu to deal with them one at a time.

Kindle devices and apps from the fourth generation onward can display AZW, AZW3, TXT, PDF, DRM-free MOBI files, and PRC files natively. You can also email HTML, DOC, DOCX, JPEG, GIF, PNG, and BMP files to your Kindle, and Amazon will convert them for you—or you can use Calibre to convert and load them without having to use e-mail. There are also some file types, like EPUB or Microsoft’s old LIT format, that can’t be converted by email, and Calibre will handle those, too.

If I attempted to write a comprehensive guide to Calibre, it would be the length of a book, so I’ll hit the basics here and then discuss how the act of copying files to a Kindle works with it. If you’d like to find out more about it, there are plenty of good tutorial articles and user guides on the subject, both here and elsewhere. If you’re wanting to break the DRM on your e-books, there’s a Calibre plug-in for that, too—but given that explaining how to do it contravenes US law, you’ll have to Google for it if you really need to know.

When you load e-books into it, Calibre creates a library directory on your hard drive, and organizes the books in subdirectories of that directory. If you keep your Calibre library on Dropbox, you can use Calibre on multiple computers at once to access it. (However, Google Drive makes some changes to file names when you upload to it, so it won’t work properly with Google Drive.) Once they’re part of your Calibre library, they show up in a list of books that you can sort by various categories. You can then convert them from one format to another; modify CSS settings like paragraph indentation, justification, or spacing between paragraphs; adjust metadata; add new cover art; view them in a fairly primitive e-book reading screen; edit them in a fairly primitive e-book editing application; and do a number of other things. And you can also load them into compatible e-reading devices that you plug in—not just the Kindle, but also Kobo, Nook, and other e-readers as well.

When you plug an e-reader such as the Kindle into your computer and launch Calibre, Calibre will detect the reader and communicate with it to find out what e-books it has on board. (Depending on how full your Kindle is, this process can take a minute or more, so be patient.) Once it’s gotten that information, it adds another column to the book list with check marks in it to show which e-books are on the Kindle at the moment.

calibre-send-to-deviceimageThe process of loading a book onto your Kindle is very simple. Simply click on the book or books in the list, right-click on the selected titles to open the context menu, then mouse over “Send to device” and select “Send to main memory” from the submenu that pops up. (The Kindle doesn’t have additional memory, so those options are greyed out.) It’s possible that some of your books may not be in the MOBI format the Kindle needs yet, in which case Calibre will offer you the option to convert them automatically. (You’ll have to click on “Show Details” to see which ones they are.)

Calibre will then churn away for a while, converting any files if necessary and then transferring them to your Kindle. If you want to see how quickly it is completing these tasks, click on the “Jobs” icon at the extreme lower right of the screen to pop up the “Jobs” screen that will show you exactly what’s going on.

calibre-deviceBut what if you have an e-book on your Kindle that’s not in your Calibre library yet? You can find out by switching Calibre over to showing what books are on your device. At the top of the screen, click on the downward-pointing triangle just to the right of the icon labeled “Device”. Then click on “Show books in the main memory of the device.” You’ll switch over to a screen that lists all the books on your Kindle, with the check marks showing which ones are also in your library.

From here, you can select any books that aren’t in your library, right-click on them, and choose “Add books to library.” Note that this won’t work with all books you buy from Amazon, because some of them may be in the KFX “virtual book format” which must be separately downloaded from Amazon. You can also delete unwanted e-books from your Kindle without having to go through the bother of selecting them one by one from the Kindle’s screen—very handy if you need to get rid of a bunch of them at once. When you’re done, just click on the triangle next to “Library” at the top to switch back to your Library view.

Here’s something you might not have known: Calibre can store and back up DRM-laden Kindle books without breaking the DRM on them. It won’t let you view or convert them to other formats because of the DRM, but it will store them in its directory on your local computer, and you’ll be able to read them again on your Kindle simply by transferring them back.


  1. Two things not mentioned are that Caliber can convert ODT files from Libre Office to other formats for your Kindle or other e-reader.

    For Mac users, Calibre can connect to and deal with Kindle Fire tablets that use the media file transfer protocol that the Mac does not natively support.

  2. Send to Main Memory is one way to get books from a computer to an ereader but it’s not necessarily the best. First, Calibre puts a *lot* of crap onto the ereader in addition to the book itself and if storage is an issue, that’s a consideration

    Second, that approach sends the book to the documents folder, without any control about where it goes beyond that. Kindle doesn’t understand folders, of course, but managing a large library on the device is a whole lot easier if the titles are separated into folders in some fashion; by genre for instance.

    Choosing the Save to Disk option fixes all that. It allows you to save the ebook to a folder on your pc then drag only the ebook to where you want it on your ereader.

    Save to Disk selected Thrillers from your library, for instance, and you can then copy those to a Kindle\Documents\Thrillers folder. Be sure to define author_sort as an output option in the ebook options type and in the name of the Save to Disk option to get your books listed by author’s last name first. Do that for all genres (or by author if you choose) and you’ll have an organized grouping of books that you can manage manually.

    So why not just use Calibre’s ability to manage books on your ereader — deleting them, for instance? Because it is unreliable and many times it will *tell* you that it has deleted the book when it hasn’t.

    Of course, if you’re smart enough to have an Android-based e-ink reader rather than a Kindle, this method will instantly organize your library; accessed from the device itself. No more messing with Kindle’s collections and no more ridiculous indexing time. Add to that the better typography control available with Android ereading softwqre and you have more than enough reasons to never buy another Kindle.

The TeleRead community values your civil and thoughtful comments. We use a cache, so expect a delay. Problems? E-mail