## Main Ebook Formats
- **EPUB 3**: open W3C standard. The most universal ebook format.
- **MOBI**: legacy Mobipocket format. Deprecated by Amazon since August 2022.
- **AZW3 (KF8)**: Amazon's modern Kindle format. Kindle and Kindle apps only.
- **PDF**: not a native ebook format but widely used.
## EPUB: The Open Standard
EPUB compatibility:
- ✅ Kobo, Apple Books, Google Play Books, Adobe Digital Editions
- ✅ Moon+ Reader, Aldiko (Android)
- ❌ Kindle (Amazon accepts EPUB on KDP since 2022 but converts it to AZW3)
## MOBI: Deprecated
Amazon stopped accepting MOBI on KDP in August 2022. Older Kindles still support it but the format lacks modern features.
## AZW3: Modern Kindle Format
Full HTML5 and CSS3 support. Kindle Paperwhite, Kindle Oasis, Kindle apps on iOS/Android. Not compatible with non-Amazon readers. Amazon auto-generates AZW3 when you upload EPUB.
## Format Comparison
| Format | Kindle | Kobo | Apple | Open |
|--------|--------|------|-------|------|
| **EPUB 3** | ❌ (indirect) | ✅ | ✅ | ✅ |
| **MOBI** | ✅ (legacy) | ❌ | ❌ | Partial |
| **AZW3** | ✅ | ❌ | ❌ | ❌ |
## Convert with Calibre
```bash
ebook-convert book.epub book.mobi
ebook-convert book.epub book.azw3
ebook-convert book.mobi book.epub --output-profile kindle_pw3
```
## Convert with Pandoc
```bash
pandoc book.docx -o book.epub --metadata title="Title"
pandoc chapters.md -o book.epub --epub-cover-image=cover.jpg
```
## Publishing on KDP
Amazon KDP accepts EPUB (recommended), DOCX, and HTML. MOBI is no longer accepted since August 2022.
Workflow: write in Word → upload EPUB → Amazon generates AZW3 → preview with Kindle Previewer.
## Which Format to Choose?
| Situation | Format |
|-----------|--------|
| Publishing on Kindle | **EPUB** (KDP converts it) |
| Publishing on Kobo, Apple, Google Play | **EPUB 3** |
| Multi-store distribution | **EPUB 3** |
| Fixed-layout technical document | **PDF** |
## Conclusion
**EPUB 3** is the standard format for modern publishing. Amazon accepts EPUB on KDP and converts it to AZW3. The old MOBI is deprecated. For multi-store compatibility, EPUB 3 guarantees maximum reach.
Guide