What happens when you convert PDF to MOBI
- The PDF is converted by Calibre, the widely used open-source e-book manager, on our conversion server.
- A PDF has fixed pages rather than flowing text, so Calibre rebuilds the text flow from the page layout. Plain books such as novels convert well; columns, footnotes, tables and headers may come out in the wrong order. Scanned PDFs are images of pages with no text, so they do not convert.
- MOBI is an older Kindle format: Send to Kindle no longer accepts it, but older Kindles and the Kindle apps still read it. For a current Kindle, AZW3 or EPUB is the better choice.
- This conversion runs on our 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. Files up to 25 MB are accepted.
How to convert PDF to MOBI online
- Press "Choose PDF files" and select one or more files, or drag them onto the box. Files up to 25 MB each can be converted.
- There are no settings to choose: the converter keeps everything the target format can hold.
- Press "Convert to MOBI". The file is uploaded to our conversion server, converted in a few seconds, and deleted together with the result as soon as the result is sent back.
- Save each MOBI with its download button. Our server has already deleted both your PDF and the MOBI by then.
Why convert PDF to MOBI?
PDF files usually come from documents, forms, invoices and print-ready files. People convert them to MOBI because MOBI is what older Kindles and the Kindle apps read.
In short, PDF is good at what it was made for, and MOBI is the more practical choice when the file has to open, upload or print somewhere else. PDF opens in every browser's built-in viewer, while MOBI opens on older Kindles and in the Kindle and Calibre apps.
How to convert PDF to MOBI on Windows, Mac, iPhone and Android
On Windows
Open this page in Chrome, Edge or Firefox, drag your PDF files in from File Explorer, and press Convert. Each MOBI is saved to your Downloads folder.
On a Mac
Safari, Chrome and Firefox all work. Drag the PDF files from Finder onto the drop zone and the MOBI files land in Downloads.
On iPhone and iPad
Open the page in Safari and tap Choose PDF files. You can pick from Photos or from the Files app. The converted MOBI appears in Files, in the Downloads folder.
On Android
Open the page in Chrome, tap Choose PDF files and pick them from Files or your gallery. The MOBI is saved to the Download folder, where any file manager can find it.
Best settings for PDF to MOBI
There are no settings: Calibre keeps the book's own styling, cover and table of contents, and the reading app decides the font size.
For the best result from a PDF, use one made from a text document rather than a scan, with a single column of text.
PDF vs MOBI: the differences
| MOBI | ||
|---|---|---|
| Full name | Portable Document Format | Mobipocket e-book |
| Type | document | e-book |
| Created by | Adobe | Mobipocket, later Amazon |
| First released | 1993 | 2000 |
| Compression | Lossy or lossless | Lossless |
| Transparency | No | n/a |
| Animation | No | n/a |
| Vector or raster | Vector | n/a |
| Colour | any colour, pages can mix text, vectors and images | n/a |
| What it holds | any colour, pages can mix text, vectors and images | a book's text, images and table of contents |
| In a browser | opens in every browser's built-in viewer | opens on older Kindles and in the Kindle and Calibre apps |
| Common uses | documents, forms, invoices and print-ready files | older Kindle e-readers and e-books from the 2000s |
| MIME type | application/pdf | application/x-mobipocket-ebook |
About PDF and MOBI files
What is a PDF file?
A PDF fixes the layout of every page so it looks the same on any device. Converting a PDF to an image renders each page to pixels; converting an image to PDF wraps it as a page.
What is a MOBI file?
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.
PDF to MOBI not working? Common problems
- "Files up to 25 MB can be converted." Server conversions have a size limit. Compress the images in the document, or split it, and try again.
- "The conversion took too long and was stopped." Very long or complex documents can exceed the time limit. Split the document and convert the parts.
- The document will not convert. It may be password protected, damaged, or saved in a newer or unusual version of the format.
Convert PDF to MOBI from the command line
This page uses Calibre. Installed on your computer, its ebook-convert command does the same conversion:
ebook-convert input.pdf output.mobiConverting 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.
PDF to MOBI converter FAQ
Will I lose quality converting PDF to MOBI?
The words are kept, but a PDF's fixed layout has to be turned into flowing text, so complex pages can come out jumbled. Plain books convert well.
Why is the MOBI a different size from the PDF?
The two formats store text and pictures differently, so the MOBI can be somewhat larger or smaller than the PDF. Images are carried over as they are.
Are my PDF files uploaded?
Yes, for this conversion. A faithful PDF to MOBI conversion needs Calibre, the open-source e-book manager, which cannot run in a browser. The file travels over an encrypted connection, is converted in a private temporary folder, and is deleted together with the MOBI as soon as the result has been sent back to you. We do not keep, read or share it.
Can I convert several PDF files to MOBI at once?
Yes. Select or drop as many files as you like; they are converted one after another and each gets its own download button.
How do I open a MOBI file?
MOBI opens on older Kindles and in the Kindle and Calibre apps. MOBI is common for older Kindle e-readers and e-books from the 2000s.
Is this PDF to MOBI converter free?
Yes. There is no sign-up and no watermark. Because this conversion uses our server, there is a fair-use limit of 25 MB per file and a number of files per hour, which stops the service being overloaded.
Can I convert PDF to MOBI on my phone?
Yes. It works in Safari on iPhone and iPad and in Chrome on Android. The conversion happens on our server, so it is as fast on a phone as on a computer; the MOBI is saved to your Downloads folder.