EPUB vs MOBI: Complete Comparison
MOBI was Amazon's proprietary ebook format for Kindle devices. In 2023, Amazon stopped accepting MOBI uploads and now supports EPUB natively via Send to Kindle. Here's what this means for you.
Key Differences
| Feature | EPUB | MOBI |
|---|---|---|
| Status | Active, W3C standard | Deprecated by Amazon |
| Kindle support | Yes (via Send to Kindle) | Legacy only |
| Other readers | Apple Books, Kobo, Play Books, etc. | Almost none |
| Max file size | No limit | ~650KB for older Kindles |
| Audio/video | EPUB 3 supports both | No |
| Accessibility | Full support | Limited |
Should You Still Use MOBI?
No. EPUB is now the universal standard. Amazon accepts EPUB via email, the Kindle app reads it after conversion, and no other platform requires MOBI. If you have MOBI files, convert them to EPUB using Calibre.
What About AZW3/KFX?
AZW3 and KFX are Amazon's newer proprietary formats. When you send an EPUB to Kindle, Amazon converts it to KFX internally. You don't need to worry about these formats — just use EPUB and let Amazon handle the rest.
Send Your EPUBs to Kindle
Read our step-by-step EPUB to Kindle guide for the easiest methods.
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