Free · Private · In your browser
EPUB to KEPUB Converter
Give your Kobo faster page turns, reading stats and better highlighting. No Calibre plugin required.
Files never uploaded Works offline Free, no signup No file size limits
How it works
- Drop any EPUB into the box above.
- The converter adds Kobo’s reading markup to every chapter – your book’s content is untouched.
- Download the .kepub.epub and copy it to your Kobo over USB.
Why “no upload” matters
Every conventional converter site works the same way: your file travels to their server, sits in their queue, gets converted on their hardware, and – you hope – gets deleted afterwards. You can’t verify any of it. The FBI has even warned about free converter sites that use that upload as a way to deliver malware or harvest the documents themselves. Your books are yours; a format change shouldn’t require handing them to a stranger.
ebook.tools removes the question entirely. The converter is delivered to your browser as code and runs on your machine; the file you drop is opened from memory, transformed, and saved back – the network isn’t involved at all. That isn’t a policy promise, it’s an architecture, and you can test it: load this page, switch off your wifi, and convert. It works exactly the same, because there was never anything to send.
What KEPUB actually is, and why Kobo readers want it
KEPUB is not a different format – it's an EPUB with Kobo's own reading annotations layered in. Kobo devices ship two reading engines: an old, conservative one for plain EPUB, and a much better one (the same engine that renders books bought from the Kobo store) that only activates for KEPUB files. The transform wraps each sentence of your book in lightweight markup spans that the modern engine uses to track position precisely.
The difference on-device is immediately noticeable. Page turns get visibly snappier, because the engine paginates smarter. Reading statistics start working: time left in chapter, time left in book, pages-per-session. Highlighting becomes accurate to the sentence instead of grabbing loose ranges, footnote pop-ups open in place rather than jumping you across the book, and full-text search gets faster.
The traditional way to get KEPUB files is installing Calibre plus the kepubify plugin, configuring an output profile, and running your library through it. That's a fine workflow for people who already live in Calibre – and overkill if you just want this one book to read nicely tonight. Here you drop an EPUB, get a .kepub.epub back, and you're done. Nothing installed, nothing uploaded.
Getting it onto the device: connect your Kobo over USB and copy the file into its storage. The double extension .kepub.epub is the trick – the filename tells the firmware to use the good engine, so don't rename it to plain .epub. Eject, let the Kobo finish importing, and open the book: if you see reading stats in the footer, the transform is active.