Free EPUB to MOBI converter

EPUB to MOBI converter for old and new Kindles

To convert EPUB to MOBI, choose your file: epubwise writes both Kindle formats into one .mobi with real chapter headings, free and without an account. Sending by email or app? You don't need MOBI at all.

Convert an EPUB to MOBI

  • No sign-up
  • Deleted within an hour
  • Opens in any reading app

Free: 10 files a day. Only convert books you have the right to convert. DRM-protected books, such as most store-bought Kindle books, can't be converted.

se_pride.mobi epubwise
se_pride.mobi                       1,388 KB

Old format, for early Kindles            yes
Modern format, for newer Kindles         yes
Real chapter headings                     66
Pride and Prejudice and a short test book with no cover, read from each file with Calibre's own inspector. This shows what the files hold: it is not a photograph of a Kindle.

Do you still need a MOBI file?

Probably not, if you use Amazon's Send to Kindle: it takes EPUB files directly and no longer lists MOBI among the formats it accepts. Our page on sending an EPUB to a Kindle walks through it.

MOBI still earns its place in three cases: copying a book over a USB cable to a Kindle that is never online, an old reading app or device that only knows Amazon's formats, and libraries of MOBI files you want to keep consistent. For newer Kindles, the AZW3 format keeps more of the book's styling.

Putting the MOBI on a Kindle by cable

  1. Convert

    Use the box above and save the .mobi file.

  2. Plug in

    Connect the Kindle to your computer; it shows up like a USB drive.

  3. Copy

    Drag the file into the Kindle's documents folder, then eject the Kindle.

How it compares: 4 EPUB to MOBI converters tested

Tested 4 and 5 November 2026. Pride and Prejudice (the Standard Ebooks edition) and a short book with no cover went through each converter's free tier with default settings and no account. One script measured every file the same way, and Calibre's own inspector counted what is inside each MOBI.

ConverterPart modern Kindles read Real chapter headingsCover for a book with none Text keptFile size
epubwise Calibre 9.17, set up for today's Kindles Yes66Yes100.0%1,388 KB
Calibre (default settings) Calibre 9.13, the desktop program No0No99.9%874 KB
FreeConvert No0No99.9%874 KB
online-convert.com No0No99.9%874 KB

What the numbers say. A MOBI file can hold two versions of a book: the old format from the first Kindles, and the newer one, called KF8. Calibre's default writes only the old format, and the sites tested gave us the same result. On a plain novel the old format holds up: alignment, margins and italics come through. What it loses is structure. Chapter titles become styled paragraphs, so Pride and Prejudice has no real headings, and small capitals become typed capitals in a smaller size, so "Dear Sir," is stored as "DEAR SIR,". Its newer version has 66 real headings and the true text. epubwise writes both versions into one file, so a Kindle that can read the new part gets it and an older one still gets the old part.

Books with fonts of their own should gain more, because the old format can't hold them, but our test books had none, so we haven't measured that.

A book with no cover stays that way everywhere else, which leaves a blank tile in the library. epubwise makes a plain cover from the title and author, and leaves any book that has a cover alone.

Where others did better: their files are smaller, because they hold one version of the book instead of two (874 KB against 1,388 KB here). Words came through the same everywhere. These numbers come from inside the files; we did not test them on a physical Kindle. CloudConvert, Convertio and AnyConv aren't in this table because they haven't been measured on these books yet.

Good to know

Our MOBI carries both Kindle formats, so it is larger than a plain MOBI. DRM-protected EPUBs can't be converted. The conversion runs on Calibre, the free ebook program, set up by us on our server, and the file is deleted within an hour.

Questions

Does Send to Kindle still accept MOBI?

Amazon's help page no longer lists MOBI among the file types Send to Kindle accepts. Send the EPUB instead; MOBI is for copying to a Kindle over USB.

Will the MOBI look exactly like the EPUB?

Close. Our MOBI holds both Kindle formats, so a newer Kindle can read the fuller version and an older one reads the plainer version. The other converters we tested write only the plainer one.

Why is this MOBI bigger than other converters' files?

It holds two versions of the book, one for each kind of Kindle. In our test that made it about 1.6 times the size of a plain MOBI, which is still small on any Kindle.

Kindle and Send to Kindle are trademarks of Amazon.com, Inc. epubwise is not affiliated with Amazon.