Book Batcher

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

As many as you like. Each one becomes a MOBI named after the book, not the file.

Output format

MOBI The older Kindle format. Simple, universally accepted by Kindle software, 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: every piece of Kindle software reads it, including current devices and Send to Kindle.

Getting it onto the device

Plug the Kindle in over USB and copy the file into the documents folder, then eject it. Send to Kindle also accepts a MOBI, but it goes through Amazon’s servers — if the point of converting locally was to keep the book off someone else’s computer, use the cable.