EPUB to MOBI: You Probably Don't Need This Anymore

If you're looking to convert EPUB to MOBI for your Kindle, good news — you don't have to. Amazon deprecated MOBI in 2022 and stopped accepting it entirely in late 2023. Your Kindle now accepts EPUB directly. No conversion, no extra tools, no workarounds. The format you already have is the format your Kindle wants.

Skip the MOBI conversion

You don't need to convert anything. Kindle has accepted EPUB directly since 2022. Amazon stopped accepting MOBI files in late 2023. The conversion step that used to be necessary is now pointless.

If someone told you to convert to MOBI, that advice is outdated. EPUB is the standard now.

Send your EPUB directly to Kindle

Upload your EPUB to DropKind and it arrives on your Kindle wirelessly in under a minute. No conversion, no cables, no email attachments.

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That's it

Your book shows up in your Kindle library with formatting, chapters, and images intact. One fewer step than the old MOBI workflow.

What was MOBI?

MOBI was Amazon's ebook format for Kindle. It powered the Kindle ecosystem for over a decade — from the original Kindle in 2007 through the early 2020s. If you wanted to sideload a personal ebook onto your Kindle, you had to convert it to MOBI first. Tools like Calibre made this painless, but it was always an extra step. MOBI was functional but limited. It was a product of an earlier era of ebook technology.

Why Amazon killed MOBI

MOBI had real technical limitations. Poor CSS support meant publishers couldn't control layout or typography. No embedded fonts. Limited image handling. No support for modern ebook features like pop-up footnotes or complex chapter hierarchies. EPUB, the open standard used by every other ebook platform, had none of these problems. In 2022, Amazon added native EPUB support to Send to Kindle. In late 2023, they stopped accepting MOBI files entirely. The writing had been on the wall for years.

What to do with your existing MOBI files

If you have a library of MOBI files, convert them to EPUB using Calibre. It's free, open source, and handles batch conversion well. Select your MOBI files, click "Convert books," choose EPUB as the output format. For an entire library, use "Bulk convert." Your books will actually look better as EPUB — better typography, better spacing, better image rendering. Once converted, send them to your Kindle with DropKind.

If you still need MOBI for an older device

This is an increasingly rare edge case, but it exists. Some very old Kindle models (pre-2022 firmware) or third-party e-readers may still require MOBI. If that's you, Calibre can convert EPUB to MOBI — just reverse the process. But if your device is that old, it may be worth updating the firmware or considering an upgrade. For everything else, EPUB is the path forward. See our guide on sending MOBI to Kindle for more detail on what changed.

Frequently Asked Questions

Can I still sideload MOBI files via USB?

On some older Kindle models, yes. You can connect your Kindle via USB cable and copy MOBI files to the documents folder. But this only works on older devices with older firmware. Newer Kindles may not recognize MOBI files at all. Wireless delivery via EPUB is more reliable and much easier.

What about AZW3 files?

AZW3 is Amazon's proprietary format, essentially an enhanced MOBI. It's also being phased out. Amazon's direction is clear — EPUB is the standard going forward. If you have AZW3 files, Calibre can convert them to EPUB. For new books, stick with EPUB.

Will my existing MOBI library still work on my Kindle?

Books already on your Kindle will continue to work. The issue is getting new MOBI files onto your device. Amazon's Send to Kindle service no longer accepts MOBI. USB sideloading may work on older models but isn't guaranteed on newer ones. Converting to EPUB is the safest long-term move.

What's the difference between EPUB and MOBI?

EPUB is an open standard supported by virtually every ebook platform and device. MOBI was Amazon's proprietary format. EPUB supports modern CSS, embedded fonts, better image handling, and complex layouts. MOBI supported none of that. Amazon recognized this and switched to EPUB. For a deeper look, see our guide on MOBI files and Kindle.

Are there any free EPUB to MOBI converters?

Calibre is the best free option — it's open source and handles the conversion well. But before you convert, ask yourself if you actually need MOBI. If you're sending books to a Kindle made in the last few years, EPUB works directly. Converting to MOBI is a step backward in formatting quality.

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