What is Mobi Format?

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What is mobi format? As one of the most commonly used file format, .mobi file is originally developed for Mobipocket reader and purchased by Amazon later. However, it is hard to get Mobi format file from Kindle store now. Instead, when you download some books from website like Project Gutenberg, if you choose kindle format, the books you downloaded will be in Mobi format. It is obviously that mobi is still one of the most widely adopted ebook format for now. Today, I will share the comprehensive knowledge of mobi format so that you can get most of it.

1. What is Mobi Format?

what is mobi format

Since the mobi format is designed for mobile device and eReader with smaller screen, it is light weight in size and contains images no larger than 64KB. However, as the first exclusive format of Amazon ebook, it is based on an open-standard ebook format using HTML and Javascript, and also supports file compression, indexing and even dictionary very well. Usually, the mobi file is also with the extension of .prc or .mobi. Most of the mobi files are DRM-free. If they are with DRM protection, they will be transformed to AZW or KFX format. Nowadays, the majority of Kindle content are with .azw3, azw, or KFX which are all the successors of mobi format with DRM protection.

What's the difference between .mobi and .prc?
The .mobi extension means that the file is a Mobipocket eBook while the .PRC is in fact a Palm software application container. It can contain a MobiPocket eBook, but it can also contain totally unrelated things. PRC was the file extension originally used, later changed to .mobi to reflect the Mobipocket name. There may be slight differences in supported formatting. But if you change the .prc extension to mobi. , the file still work. Please note: .prc files may be protected with DRM. If they are with DRM protected, they won't be usable untill they are cracked.

2. How to Open Mobi File?

Since mobi is not normal format, you cannot open  mobi file on PC or Android device by default. Here are some apps or devices support mobi format natively.

  • Kindle devices—Kindle eReaders and Kindle Fire Tablets.
  • Kindle apps— Kindle for PC, Kindle for Mac, Kindle for iOS, Kindle for Android, Kindle previewer.

Besides above mentioned devices and apps, there are many reading apps can help you open and read mobi files, such as Calibre. Book Bazaar Reader, SumatraPDF Reader, Mobipocket Reader ect.

If you want to open mobi file on PC, please read Best MOBI Readers for Windows. Once you have downloaded the mobi file, right click it and choose the apps to open it. All done.

If you want to open mobi file on Android, please add mobi to kindle for Android for reading.

If you want to open mobi file on iOS, here is Read Mobi on iPad.

open mobi file

3. How to Convert Mobi Files?

I know many ebook lovers choose to purchase ebooks from Amazon but purchase Kobo eReaders because Amazon has the largest amount of ebook titles while Kobo eReader is much cheaper than Kindle. Are you one of them? If yes, you will know that mobi files are not compatible with Kobo eReader at all. Actually, most eReaders don’t support Kindle mobi format.  Hereby, we need to convert mobi file to  epub or pdf format which are accepted by most of the eReaders among the market.

There are many tools you can choose, such as Calibre—free ebook converter or Convertio--online mobi to pdf converter. To be mentioned, if you purchase Kindle books frequently, DRM protection can be a problem when converting kindle books. The above mentioned ebook converter can only handle DRM free kindle books. So to handle kindle books smoothly, Epubor Ultimate can be the top-priority because it is the best ebook DRM Removal as well as the ebook Conveter.

Step 1 Download and install Epubor Ultimate.


Step 2 Remove Kindle DRM and convert mobi to EPUB/PDF/TXT.

Ensure your kindle books have been downloaded to computer or Kindle eReader. Run Epubor Ultimate, the downloaded kindle books will show at the left column under Kindle or device tab. Just drag them from left to the right column, the DRM will be removed.

Then select your output format from the central buttom button, then click on "Convert to xxx", the kindle books will be converted. Once finished, you will see "Successfully" at the end of each book.

convert mobi file

Please note: Epubor Ultimate can handle both DRM free or DRM-protected kindle mobi files.

Tip 1: It is hard to get Mobi format file from Kindle store now.
We have downloaded almost 4 thousands books, but no one is in mobi format. It strongly proves that Amazon has already abandoned mobi format. In contrast, almost all downloaded kindle books are in kindle kfx or azw format which are protected by new kindle DRM.

Tip 2: How to convert epub/pdf/kfx/azw to mobi?
Although Amazon tries hard to replace its ebooks with Kindle kfx format, when converting other ebook formats to kindle, mobi still be the first choice. Compared with other kindle format, mobi is the only format that is compatible with all kindle devices and apps. You can also follow the above steps to convert epub, pdf, kfx, azw to mobi file for better reading experience.

Although there are many successors of mobi format, mobi format is still the widely adopted kindle format outside the Kindle store. I think it is not so easy for Amazon to abandon this format as there are many old Kindle devices are still hold by ebook lovers. These are all knowledges about mobi format I want to share. If you have any more questions about this format, please leave it in the comments so that we can dig it deeper.

If you happen to download kindle mobi format with DRM protection, Epubor Ultimate can help you decrypt and convert it now. Just download it for free trial now.



joined Epubor since 2017. She always wants to share everything related to ebook reading and improve your reading journey.

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