# What is MOBI?

Source: https://epubcc.com/glossary/mobi/ (updated 2026-11-04)

MOBI is the older Mobipocket-based e-book format that early Kindles used, with the .mobi extension. Amazon's Send to Kindle help page no longer lists it among the supported formats, while it does list EPUB.

## Why it matters when you convert a PDF to EPUB

Many guides still tell you to convert a PDF to MOBI for a Kindle. Today that is the wrong target: Amazon's current list of formats for personal documents includes EPUB and PDF but not MOBI, so a converted PDF should be an EPUB sent with Send to Kindle.

Amazon's troubleshooting page still has an error for invalid or corrupted MOBI files (E002), and KF8 (AZW3) replaced MOBI as the Kindle's own book format. Both pages were read on 2026-11-04.

How EpubCC handles it: it does not write MOBI, KF8 or AZW3. It writes EPUB 3, the format Send to Kindle accepts, and the same file also works on Kobo, PocketBook and other readers.