MOBI is the legacy Amazon Kindle format. While newer Kindles accept EPUB directly, old Kindle hardware (pre-2022) and some sideload workflows still expect MOBI.
Convert EPUB to MOBI – Free Online EPUB to MOBI Converter
Why convert EPUB to MOBI?
- Send to old Kindle devices that don't accept EPUB.
- Use Send-to-Kindle workflows that prefer MOBI input.
- Maintain compatibility with legacy Kindle libraries.
What is the difference between EPUB and MOBI?
| EPUB | MOBI | |
|---|---|---|
| Format status | Open standard used by every non-Kindle reader | Amazon's Mobipocket-era legacy format |
| Kindle device support | Modern Kindles only | Every Kindle ever made, including pre-2012 models |
| Send-to-Kindle email | Accepted | Rejected since 2022 — USB transfer only |
| Typography | Full CSS and embedded fonts | Basic renderer — custom fonts and most styling ignored |
| Best for | Current devices and reading apps | Sideloading onto legacy Kindle hardware |
Does converting EPUB to MOBI lose quality?
MOBI's rendering engine dates from the 2000s, so treat this conversion as a simplification pass. Body text, chapter breaks, italics, and inline images translate reliably; embedded fonts, custom CSS, drop caps, and fine spacing controls are quietly dropped, and the Kindle's default typeface takes over. For a plain novel the difference is nearly invisible; a heavily designed EPUB comes out plainer but perfectly readable.
Give the metadata a look before transferring. Title and author carry across and determine how the book files itself in the Kindle library, so fix any blanks in the source EPUB first. Covers embed correctly, but some older Kindles show a generic thumbnail for sideloaded books on the home screen even though the cover displays once opened — a long-standing device quirk, not a conversion fault.
What can go wrong converting EPUB to MOBI?
- Send-to-Kindle refuses the MOBI I just made — Amazon dropped MOBI from Send-to-Kindle in 2022; the email route now wants EPUB or PDF. MOBI is for USB transfer — connect the Kindle and copy the file into its documents folder. If email is your only delivery path, send the original EPUB instead.
- The conversion fails on a book I bought from an ebook store — The conversion fails because the book is DRM-protected; we cannot and do not remove DRM. Only DRM-free EPUBs — from Project Gutenberg, DRM-free storefronts, or your own documents — will convert.
- Chapter navigation doesn't work on the Kindle — The MOBI's table of contents is built from the EPUB's navigation document; if the source EPUB shipped without one, there's nothing to build from. Generate a TOC in Calibre or Sigil first, then convert again.
How to convert EPUB to MOBI
- Upload your EPUB file using the area above.
- MOBI is preselected as the target format.
- Click Start and wait for the conversion to finish.
- Download your converted MOBI file.