EPUB → MOBI
EPUB to MOBI
Kindle hardware does not open EPUB files from a USB cable. MOBI is the format it has always read, and this converts to it in your browser — with a contents list that actually works, which is the part most converters get wrong.
No upload · Files are read in this tab and never sent anywhere
Intake
Drop EPUB files here
Output format
MOBI — The older Kindle format for compatible devices via USB, with limited styling.
What survives
- Title, authors, publisher, date, subjects, description and ISBN.
- Every chapter, in the reading order the package declared.
- Images, including the cover, which is marked so a Kindle shows it in the library.
- A working table of contents. MOBI has no filenames and no anchors, so links are byte offsets into one long document — they are measured after the book is laid out and patched in, which is why they land on chapters rather than nowhere.
- A guide, so “Go to → Beginning” and “Table of Contents” work on the device.
What does not
- The book’s stylesheet and any embedded fonts. MOBI has no support for either, and the conversion says so on the file it produces.
- Fixed page layout. MOBI always reflows, so a comic or an illustrated children’s book is better converted to EPUB or PDF.
- Right-to-left page progression, which MOBI cannot express.
Why not AZW3
AZW3 output is not offered. Writing Kindle Format 8 correctly means building the skeleton, fragment and index records a Kindle uses to paginate, and a file that opens but paginates wrongly is worse than one that was never offered. MOBI is written instead for compatible Kindle devices via USB. Use EPUB for Send to Kindle.
Getting it onto the device
To sideload the MOBI on a compatible Kindle, connect it over USB and copy the file into the documents folder, then eject it. For Send to Kindle, use the original EPUB instead. That service uploads the book to Amazon’s servers; use the cable to keep the transfer local.
Questions
- Will the table of contents work on my Kindle?
- Yes. MOBI links are byte offsets into one long document, so they are measured after the book is laid out and patched in. The contents list and the Kindle’s “Go to” menu land on the chapters.
- Should I convert to MOBI for Send to Kindle?
- No. Send to Kindle accepts EPUB, and Amazon no longer takes MOBI through it. Send the original EPUB; convert to MOBI only for copying onto a Kindle over USB.
- Is the formatting kept?
- The text, chapters, images, cover and metadata are. The book’s stylesheet and embedded fonts are not, because MOBI supports neither, so the Kindle shows the book in its own type.
- Can I convert several EPUB files at once?
- Yes. Drop as many as you like; each becomes its own MOBI named after the book, and once more than one is finished they can be downloaded together as a ZIP.
- Is my book uploaded?
- No. It is converted inside this browser tab and saved with the browser’s own download. The page’s security policy blocks connections to any other server.