.mobi — Mobipocket Ebook
An older ebook format associated with Mobipocket and early Kindle publishing workflows.
About this format
MOBI is an older ebook format that became tied to early Kindle workflows. Modern Kindle publishing has moved toward newer formats, but MOBI files still appear in archives and personal libraries.
Use MOBI only when an older device or archive requires it. EPUB is usually the better open source format today.
Real-world samples & file sizes
Four real Mobipocket files from Project Gutenberg Kindle downloads. Browsers cannot preview MOBI directly, so each card uses the matching Gutenberg cover as a visible fallback.
Dracula MOBI
A real Mobipocket file from the Kindle images download, paired with its Gutenberg cover.
Sherlock Holmes MOBI
A compact MOBI sample for older Kindle-era reading and converter checks.
War of the Worlds MOBI
A small Mobipocket ebook with cover art suitable for legacy-reader tests.
A Tale of Two Cities MOBI
A larger MOBI sample useful for archive handling and file-size checks.
Pros
- +Works with some older Kindle-era libraries
- +Small ebook files
- +Common in legacy ebook collections
Cons
- −Legacy format
- −Weaker modern layout features than EPUB
- −Limited non-Kindle relevance
MOBI vs other formats
| vs | Size | Quality | Note |
|---|---|---|---|
| EPUB | Similar | EPUB is more modern | EPUB is the better authoring and interchange target. |
| Usually smaller | Reflowable text | PDF preserves pages; MOBI preserves reading flow. |
Where it works
- Reader app required
- Browsers do not open MOBI natively
- Calibre
- older Kindle apps/devices
- ebook converters
Frequently asked questions
- Should I publish a new ebook as MOBI?
- Usually no. EPUB is the better modern source format unless a specific workflow requires MOBI.
- Can I convert MOBI to EPUB?
- Often yes with ebook tools, but DRM-protected files cannot be freely converted.
Sources
- Library of Congress - Mobipocket - MOBI format description and history