Comparing Ebook Formats: Exploring the Distinctions of Kindle KFN, KCR, AZW/AZW3, and More

Difference Between Kindle KFX, KCR, AZW, AZW3, PRC, Mobi, Topaz, AZW6

Posted by Jonny Greenwood on 6/28/2022 10:54:30 AM.

Amazon Kindle has the largest eBook collection in the world, with the most complicated eBook format mechanism. Here you can find KFX, KCR, AZW, AZW3, PRC, Mobi, Topaz, and more.

Although a Kindle book can be delivered as any of these formats and they almost look the same, actually they are not. The difference may be slight, but we can’t ignore it.

Here is a detailed introduction and explanation about Kindle formats.

If you are interested in the ebook formats beyond the Kindle books, just read General eBook formats explanation .

KFX

KFX is the latest format of Amazon Kindle. The kindle ebooks with the “Enhanced Typesettings” property enabled will be downloaded as kfx format.

KFX is the successor of AZW6, it’s even not a real eBook file. You can see it as a downloader. It downloads all the stuff of a book into your Kindle, regardless of texts or images.

So there is no change at all if you convert a KFX file to another format or decrypt a KFX file.

However, there are 3 Methods to Remove DRM from Kindle KFX eBooks .

KCR

If you downloaded a Kindle book via Kindle for Mac v 1.25.2 (and above), you will be likely to get a .kcr file. Currently there isn’t so much information about this eBook format.

Kindle .kcr is treated as the new Kindle KFX (new format, with new DRM protection technology). For more information, you can read the guide on**How to Remove DRM from KCR and Convert KCR to PDF **.

AZW

AZW is the most popular format for Amazon Kindle books. It might stand for Amazon Word, but Amazon hasn’t officially confirmed that yet.

If we download the purchased Kindle books to local computer via Kindle for PC/Mac, the books are usually saved in .azw format and protected by Kindle DRM.

If an AZW file’s DRM protection is eliminated, it can be directly converted to EPUB/PDF while keeping the file formatting original and read by any ebook reader you have.

To convert AZW to PDF/EPUB is pretty simple. Just make sure the files are downloaded via Kindle for PC/Mac, and then use AZW Converter to handle them, no extra job is required.

Here is a brief guide you may be interested: Best AZW Converter-Convert Kindle AZW to PDF/EPUB .

AZW3 (KF8)

AZW3 is a variation of AZW and also known as KF8 (Kindle Format8). It was released by Amazon in 2011 along with the release of Kindle Fire. At beginning it was only supported by Kindle Fire tablet, but later expanded to Kindle 4th generation and Kindle for PC/Mac.

Compared to AZW or Mobi, it is more advanced by supporting more styles, fonts and layouts. And it becomes a trend that AZW3 is gradually replacing Mobi.

Nowadays Kindle books directly downloaded to recent generations E-Ink Kindle or downloaded from the Amazon official website are usually saved as AZW3 format and protected by DRM. And some AZW files downloaded from Kindle for PC/Mac would also turn to AZW3 after the DRM protection is removed.

If you want to strip the DRM from AZW3 files, please read How to Remove DRM From AZW3 eBook Files .

PRC and Mobi

When a PRC file and a Mobi file are DRM-free, they’re almost the same thing. But when they are protected by DRM, they’re totally different.

PRC is a old Kindle format adopted in the Kindle books from early Kindle Android app. From Kindle for Android V7.2 and later versions, all the downloaded Kindle files are KFX format, not the old PRC format. And currently there isn’t any effective method to directly remove DRM from the Kindle KFX books via Kindle Android app (including Kindle Fire tablet).

Mobi is actually not an independent format. It can be viewed as the mixture of prc and azw3. The ebook html content is saved as 2 formats in a mobi file after processed twice, one is in prc format and the other is in azw3 format. The file format is compatible in the early Kindle ereaders which can be rendered greatly on these devices.

Nowadays most Mobi books are DRM-free, but once Amazon transforms them to AZW or AZW3, they are protected by DRM.

Topaz (TPZ, or AZW1)

Generally speaking, all the formats above are basically generated upon Mobi and AZW, but the Topaz, or the variations TPZ and AZW1, are pretty different. And the difference mainly lies in the file structure and database.

The Topaz files are always DRM-free. When they are protected by Kindle DRM, they would change to TPZ or AZW1.

If a Topaz book is synced via Kindle’s Whispersync, it becomes AZW1; if it is directly downloaded from website, it becomes TPZ.

Remove DRM from TPZ/AZW1 books are the same as from AZW, so you can also read this guide: Remove DRM from Amazon Kindle TPZ, AZW1, Topaz files .

What about the HTMLZ? It is just a zip archive of HTML files.

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AZW6

AZW6 files are very rare. They mainly appear in Japan Kindle store’s manga books.

An AZW6 file only contains texts. All the images in the book are saved in the related folder. So if you convert an AZW6 book to another format, all the images will be lost, as they are not contained in the book file.

Imagine you buy a Kindke AZW6 book (you don’t know its format before buying) in a place with poor WiFi network, then this book will download low quality images, you needn’t wait a long time to start reading the book. When you go to a place with strong WiFi, Kindle will download high quality images to replace those low quality images automatically.

PDF

Portable Document Format (PDF) is the most widely used file format which is created by Adobe. Except Amazon Kindle, almost all other retailers/devices support PDF files. Ebooks in PDF format are usually protected by Adobe adept DRM or the proprietary DRM adopted by the specific retailers.

There’re many privileges of PDF that other formats can’t compete with. PDF files can preserve and retain the original formatting of file. The display effect preserves when reading a PDF on different devices or platforms. PDF files are designed to deliver content suit for A4 or letter scale. Content in PDF is not relowable, so there might be problematic when reading PDF in a handheld device. It can provide the best display effect when reading on computers, but it’s not a good idea to read PDF files with small screens in most mobile eReaders.

If you’ve got some ebooks in PDF format and want to read them on Kindle eReaders, cellphones or tables, you’d better convert PDF to Mobi or Epub format.

For extended reading, please refer to Best PDF to EPUB Converter–Convert PDF files to EPUB format , or How to Send PDF to Kindle .

A Comparison Chart of Kindle Formats

| | Kindle (firmware lower than 5.8) | Kindle (firmware higher than 5.8) | Kindle for PC v1.21 | Kindle for MAC v1.21.1 | Kindle for iOS v6.03 | Kindle for Android v7.2 | Kindle Previewer v2.94 | |
| ———————————– | ——————————— | ——————- | ———————- | ——————– | ———————– | ———————- | - |
| prc | v | v | v | v | v | v | v |
| azw3 | v | v | v | v | × | v | v |
| mobi (prc+azw3) | v | v | v | v | O | v | v |
| kfx | × | v | v | v | × | v | × |

v: files in this format can be read on the device or with the app

×: files in this format cannot be read on the device or with the app

O: users actually read the prc content within the mobi files

Kindle for iOS can only read files with extension of azw and mobi.

Kindle for Android can read files with extension of prc, azw, azw3 and mobi. kfx files are also supported as long as the files are placed in Kindle directory of Android File Manager.

Devices/apps that can read kfx files:

1.Kindle eReaders with firmware upgraded to 5.8,for example Paperwhite2, Paperwhite3, Voyage, Oasis (the file extension must be kfx)

2.Kindle for PC and Kindle for MAC, upgrading to the latest version is recommended

3.Kindle for Android, upgrading to the latest version is recommended (the file extension must be kfx)

What’s the best eBook format for Kindle?

When asked about what’s the best eBook format for Kindle, usually I will say I don’t know.

1. Kindle supports PDF. But the fact is that the PDF reading experience on Kindle device is very poor.

2. Books we bought from Amazon Kindle store are in KFX, Mobi or AZW (azw3) format.

We can’t avoid buying epub or pdf format eBooks, and we can’t (and in fact there is no need to) buy all those main popular reading devices at hand. So talking about which one is the best is meaningless. The perfect solution is to use Epubor Ultimate , an eBook Converter tool to help you convert eBooks formats between Kindle Mobi and ePub, PDF with high quality.

Download Epubor Ultimate for Free

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Jonny Greenwood joined Epubor since 2011, loves everything about eBooks and eReaders. He seeks the methods to read eBooks more freely and wants to share all he has got with you.

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16 Comments

Cindy

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

01/21/2014 14:49:16

Thank you for that. I was having trouble with which was which. Trying to format and certain files did not indent a block quote on both sides. Mobi did not so I tried the AZW3 you mention, and it does it.

SophieD

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

05/20/2014 14:12:29

It figures that there has to be one company that makes things difficult. I’m an independent author who only wants it to be simple. Now I have to wonder if the mobi files I upload will work for my readers.

louise

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

07/2/2014 05:39:17

Why won’t my prc files show on my kindle fire but do on my dimple kindle.thanks

Jonny

Re:louise

07/9/2014 23:56:40

To transfer ebook files to Kindle tablet/ereader, I would recommend you use “Transfer to Kindle” service.

Here is the guide post: www.epubor.com/transfer-books-to-kindle-kindle-fire-hd-paperwhite-kindle-for-androidipad-app-from-pcmac.html

Bilal

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

10/8/2015 02:00:22

Hi. Thanks for this!

I was wondering if there is any Kindle format that supports embedded audio and video across all devices such as iOS, Android, PC and Mac.

Will appreciate some advice.

Thanks

Reid Anderson

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

10/22/2015 15:41:01

Thanks for this post. It’s exactly what I wanted to know. I’m converting epub for my PaperWhite and was wondering about .mobi vs. .azw3.

Epubor

Re:reid anderson

10/22/2015 15:41:03

For decrypting books from Kindle device:
1, Connect Kindle to computer with USB cable.
2, Directly drag the books from rightside column into leftside main window.

For decrypting books from Kindle for PC/Mac:
1, Download and authorize Kindle for PC/Mac with your Amazon ID.
2, Launch Kindle for PC/Mac, sync all books to your computer and make sure you can read all the books.
3, Run Epubor software, all done.

Detailed info: http://www.epubor.com/faq.html

Angel

Re:Reid Anderson

06/28/2016 19:47:33

Now the newest version of Epubor Ultimate supports output both “Mobi” and “AZW3”.

You can try to convert your EPUB to these 2 formats, then choose a better one you like.

Lily

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

11/10/2015 07:58:30

Who leaves the typo with the red squiggly underline on a published infographic? So unprofessional.

Kenneth

Re:Lily

07/27/2016 12:03:54

Bitchy a little?

Bobbette

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

12/1/2015 15:12:10

I’m having some trouble when I send non-amazon purchased books to the kindle app on my iPad Mini 3. Sometimes, the cover of the book is stripped and replaced with a generic word template with the title of the book. I’ve been trying to figure out why it only happens sometimes and I’m leaning towards thinking that only books with the AZW extension come through to the kindle app fine. I’ve sent books with the Mobi and PRC extensions and they are stripped of their covers while books with the AZW3 don’t get uploaded at all. Is there a converter out there that will convert from Mobi to AZW because all the converters I’ve found change to the AZW3 extension? Any help you can provide would be greatly appreciated. Thanks!!

Epubor Angel

Re:Bobbette

06/28/2016 19:43:37

Hi,

No, now all the converters only supports Kindle’s AZW3 or Mobi output.

I recommend you make sure you’re using Epubor Ultimate(newest version), which may solved your problems that cover stripped.

And you can also add covers to your books by metadata editing.

MARK G

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

02/5/2016 19:53:03

I have an older kindle and have been converting my epub to azw but the new converter i bought only does azw3 and does not show on my older kindle. Is there a free coverter that will convert azw3 to azw?

Guru

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

12/13/2016 03:23:33

Jonny - YOU ROCK!

Very informative, helpful and extremely well-written article.
Thank you for taking the time to write it and for sharing your knowledge.
Greatly appreciated.

student cat

Re:Difference Between Kindle Content AZW, AZW3, PRC, Mobi, Topaz

01/14/2017 02:05:56

I purchased a textbook from amazon.
I want to remove DRM so that I could sync it to iBooks (I don’t like kindle reader), and also so that one day Amazon doesn’t just decide to pull it off if the lose a contract with the publisher (like that 1984 conundrum).

So, I opened the folder where my content is stored and it has several files:

.azw4 – 190 MB
.azw – 27 MB
.mbp – 120 bytes
.phl – 1 kb
.mbpV2 – 242 bytes

I assume my main guy is .azw4 since it’s the largest file, but what’s that also pretty large 27MB .azw file for?
And what’s the purpose of the rest of the files (smaller ones)?

Should I be able to convert it to a DRM-free pdf file?

Thank you.

Epubor

Re:student cat

01/14/2017 02:05:58

For decrypting books from Kindle device:
1, Connect Kindle to computer with USB cable.
2, Directly drag the books from rightside column into leftside main window.

Detailed info: http://www.epubor.com/faq.html

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Comparing Ebook Formats: Exploring the Distinctions of Kindle KFN, KCR, AZW/AZW3, and More