What is a MOBI file?
MOBI stands for Mobipocket e-book. It was created by Mobipocket, later Amazon and first released in 2000. MOBI was the Kindle's original format. Amazon has since moved to AZW3 and KFX and no longer accepts MOBI through Send to Kindle, which now takes EPUB instead.
| Type | e-book |
|---|---|
| Compression | Lossless |
| In a browser | opens on older Kindles and in the Kindle and Calibre apps |
| Common uses | older Kindle e-readers and e-books from the 2000s |
| MIME type | application/x-mobipocket-ebook |
How to open a MOBI file
Whether a MOBI file opens with a double click depends on the device. Here is what works on each, without buying software:
| Windows | Calibre, a free e-book manager, opens every e-book format; the Kindle app opens MOBI and AZW3. |
|---|---|
| Mac | Apple Books opens EPUB; Calibre and the Kindle app open MOBI and AZW3. |
| iPhone and iPad | Apple Books opens EPUB; the Kindle app opens books sent to your Amazon account. |
| Android | Google Play Books opens EPUB; FBReader opens EPUB and FB2; the Kindle app opens Amazon books. |
| Web browser | MOBI opens on older Kindles and in the Kindle and Calibre apps. |
Want the technical details? See what a .mobi file is, with its MIME type, file signature and a viewer.
MOBI compared with other e-book formats
How MOBI stacks up against the formats people most often convert it to or from:
| Format | Compression | Usually contains | Released | Best for |
|---|---|---|---|---|
| MOBI | Lossless | a book's text, images and table of contents | 2000 | older Kindle e-readers and e-books from the 2000s |
| EPUB | Lossless | chapters as XHTML pages, with images and a table of contents | 2007 | e-books from stores other than Amazon and free e-book libraries |
| AZW3 | Lossless | a book's text, images, styling and table of contents | 2011 | Kindle e-readers and books loaded onto them over USB |
| FB2 | Lossless | a book's text, structure and metadata as a single XML file | 2004 | e-books from Russian and Eastern European libraries |
| Either | 1993 | documents, forms, invoices and print-ready files |
How to use the MOBI converter
- Choose the format you want in the Convert to menu.
- Drop your MOBI files on the box, or press Choose MOBI files. Several files can go in at once.
- Adjust the settings if you need to; the defaults suit most people.
- Press Convert and save each file with its Download button. The file is converted on our server and deleted as soon as the result is sent back.
Tips for converting MOBI files
Converting a MOBI file keeps the book's text, chapters and images; what changes is how it is packaged for each reader. A few habits give the best result.
- For a current Kindle, send EPUB through Send to Kindle, or copy AZW3 over USB. MOBI is for older Kindles.
- Books with DRM cannot be converted. DRM-free books from Project Gutenberg, Standard Ebooks and independent authors convert normally.
- Keep the original file; each conversion rebuilds the book.
- For PDF to EPUB, a PDF made from a text document converts far better than a scan or a multi-column layout.
- Calibre, the engine used here, is free for your own computer too, and handles whole libraries at once.
Convert MOBI files from the command line
This page uses Calibre. Installed on your computer, its ebook-convert command does the same conversion:
ebook-convert input.mobi output.azw3Converting on your own computer keeps the file entirely local, which is worth it for very large or very sensitive documents. For everything else, the converter on this page does it without installing anything.
MOBI converter FAQ
What is a MOBI file?
MOBI stands for Mobipocket e-book, an e-book format created by Mobipocket, later Amazon in 2000. MOBI was the Kindle's original format. Amazon has since moved to AZW3 and KFX and no longer accepts MOBI through Send to Kindle, which now takes EPUB instead.
How do I open a MOBI file?
MOBI opens on older Kindles and in the Kindle and Calibre apps. If the program you need will not open it, convert it to a more widely supported format above.
What is the most common MOBI conversion?
MOBI to AZW3 is the conversion people search for most. The MOBI is converted by Calibre, the widely used open-source e-book manager, on our conversion server.
Does converting MOBI files here upload them?
Yes. MOBI conversions need Calibre and pandoc, open-source programs that cannot run in a browser, so they run on our conversion server. The file is uploaded, converted, and deleted together with the result as soon as the result has been sent back to you. Nothing is kept.
Is the MOBI converter free?
Yes. There is no sign-up and no watermark. Conversions that use our server accept files up to 25 MB, with a fair-use limit per hour. The site is supported by advertising.
Can I convert MOBI files on iPhone or Android?
Yes. Open this page in Safari on iPhone and iPad, or in Chrome on Android, choose your MOBI files and download the results to your Downloads folder.
Can I convert several MOBI files at once?
Yes. Drop as many as you like; they are converted one after another, each with its own download button.