File formats for e-books

Whatever device you read on we have a format that works.

Before we discuss other formats, the video below shows you to transfer mobi files onto a Kindle. When you buy one of our e-books, mobi files are included in the download file. If you have a different e-book reader device (also called an e-book reader or e-reader) please read on for a list that will help you identify the correct file format to use.

Common file formats

File formats are often referred to and identified by the letters used for their file extensions, so that’s how we’re listing them here. Although there are many file formats, most devices support one or more of the following:

  • epub – The International Digital Publishing Forums’ EPUB standard. Widely adopted and supported by many e-reader devices.
  • pdf – Adobe Portable Document Format. This has a fixed page format so is not ideal for small reading devices (e-readers), but it displays well on computer screens and tablets. Widely adopted for digital documents (not just e-books) and works on the vast majority of PCs, laptops and tablets.
  • azw – Amazon’s proprietary file format. Only available from Amazon for their Kindle e-readers. (There is actually more than one Kindle format because Amazon are progressively upgrading the capabilities of their e-readers.)
  • mobi – Mobipocket’s file format. Amazon Kindle compatible, but this is not guaranteed (see note below). The mobi format remains important, mostly because of its Kindle compatibility, but its long-term prospects are not clear.

Other file formats

The following formats are still in use but will be phased out in new editions of our e-books, because most devices that use them also support one of the formats listed above:

  • pdb – eReader (formerly Palm Digital Media)
  • fb2 – FictionBook
  • lit – Microsoft Reader
  • lrf – Sony Reader (Sony appear to recommend EPUB for their newer devices)
  • opf – Open Electronic Package (Open eBook)
  • snb – Shanda Bambook e-reader.

A note about Amazon Kindle

The Amazon Kindle e-reader uses an e-book file format (file extension azw) exclusive to Amazon. The only way to purchase a genuine Amazon Kindle e-book is through the Amazon website. All of our books are available from Amazon.

However, the current Kindle models are able to read and display the mobi file format listed above; the Kindle file format is actually based on mobi and is only very subtly different. You will have to draw your own conclusions as to why Amazon do not publicise this fact.

We are confident that if you buy an e-book from us it will work on your Kindle.

Future formats

In the future there are likely to be big changes in the design and features of e-book readers and file formats. Our aim is to issue books in all major formats. Once you have bought a book from us and are registered as its owner you qualify for any new file formats free as they are released.

If you want a format not listed here please let us know by emailing

VN:F [1.9.22_1171]
Rating: 0.0/5 (0 votes cast)
VN:F [1.9.22_1171]
Rating: 0 (from 0 votes)