A Kindle can't open an EPUB you copy onto it.
Drop yours in and get a MOBI back that you can copy straight to the device over USB. The same box also goes the other way: pick EPUB in the menu to change MOBI to EPUB.
By ShinobiTools Team · Last updated: September 2026
Every converter here is free, full size, no account. Photos convert in your browser and never leave it, except camera RAW files and SVG tracing. Those, like video, audio and e-books, need our server — and we delete them right after.
This free online converter turns EPUB into MOBI without a Calibre install: the file goes to our server, Calibre's own converter does the work there, and the MOBI downloads straight back. For a normal novel the EPUB to MOBI convert step takes a few seconds.
Amazon built Kindle around its own formats instead of EPUB, which is what nearly every other e-reader and store uses. MOBI is the older of Amazon's two formats and the one that works on every Kindle ever made, including the original. If you have a Kindle from the last several years, AZW3 keeps a bit more formatting — but MOBI is the safe choice when you are not sure.
One thing changed in 2022: Amazon's Send to Kindle (the @kindle.com e-mail address, the app and the website) now accepts EPUB directly and no longer accepts MOBI. So if you send books by e-mail, you don't need this page at all: send the EPUB and Amazon converts it for you. Converting to MOBI or AZW3 is for copying a book over USB, and for older Kindles that you load by cable.
The difference between EPUB and MOBI isn't visual: a page reads the same either way. It's about which format a device will open. EPUB works on almost every e-reader and reading app except a Kindle; MOBI and the newer AZW3 are the Kindle's own. If you're weighing EPUB, MOBI and AZW3 as three options for a book you'll copy over USB, MOBI is the one that works on every Kindle ever sold, and AZW3 keeps more formatting on current models. To transform EPUB to MOBI in the box above you only need the file, because MOBI is already selected for you.
documents folder, eject, and the book appears in the library.On a phone the conversion works too, but a phone can't copy the file to a Kindle over USB. Use a computer for that last step, or send the original EPUB with the Send to Kindle app instead.
A browser cannot rewrite an EPUB's internals into Kindle's MOBI format, so your file is uploaded to our server, converted there and deleted right after. We keep no copy. Photos (HEIC, PNG, WEBP, JPG) are different: those convert entirely in your browser.
Books bought from a store usually carry DRM (copy protection). Those can't be converted here or anywhere else legitimately; the conversion only works on DRM-free EPUBs, such as your own writing, public-domain books or shops that sell without DRM. Files up to 100 MB are accepted, which covers almost any novel; picture-heavy books can come out larger.
Need to go the other way and change MOBI to EPUB instead? Pick EPUB in the menu of the box above. Used to CloudConvert EPUB to MOBI, or Zamzar MOBI to EPUB? Both upload the file to a server too and both have free tiers with daily limits. Here there's no daily limit and no account: a free converter with one limit, 100 MB per file.
You can convert EPUB to MOBI and back as often as needed; nothing is saved here, so there's no history to worry about in either direction. An EPUB conversion to MOBI hands you a new file and leaves your original EPUB exactly as it was.
Want a fixed page layout instead — good for a comic or a textbook? EPUB to PDF does that.
A Kindle only opens its own formats, MOBI and AZW3, from its documents folder. Converting here bridges that gap for books you copy over USB. With Send to Kindle, Amazon converts the EPUB for you instead.
AZW3 keeps more of the original formatting on current Kindles, which makes AZW3 files the better pick for a Paperwhite; MOBI is the safer choice for an older device, a Kindle 3 or Touch, or if you are unsure which you have. Newer Kindles also read EPUB through Send to Kindle, which converts it for you, so MOBI or AZW3 matters mainly when you copy the file over USB.
Yes. A browser cannot rewrite an e-book's internal format, so the file goes to our server, converts, and is deleted right after. The same is true for the video compressor and the other video and audio tools here; only the photo converters run entirely in your browser.
Yes, free in full: every free convert is full quality, with no account, no watermark and no per-file charge, up to 100 MB per book. It runs Calibre's own converter on our server, so it works as a Calibre EPUB to MOBI converter without installing Calibre or an app yourself, and the EPUB MOBI format settings are Calibre's defaults. Drop your EPUB onto the box above, MOBI is pre-selected, and the result downloads in seconds; that is how to change EPUB to MOBI in one step. French and German write it as "EPUB en MOBI" or "EPUB in MOBI"; same box.
Copy it over USB into the Kindle's documents folder. E-mailing it to your @kindle.com address no longer works for MOBI files: Send to Kindle stopped accepting them in 2022. For e-mail, send the original EPUB instead.
Yes: pick EPUB in the menu of the box above, or use the e-book converter, which handles any combination of EPUB, MOBI, AZW3, PDF and TXT.
The conversion works in any phone browser: pick the file, wait, save the MOBI. Getting it onto a Kindle still needs a computer and a USB cable, so on a phone the Send to Kindle app with the original EPUB is usually easier.
Pick AZW3 in the menu before you drop the file. Everything else is the same.
The most common reason is DRM: a book bought from a store is usually copy-protected, and a protected EPUB can't be converted. The other is a damaged EPUB; opening it in another reader first tells you which.
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