Ordinary converter sites run your files through their servers, which costs them money for every conversion — money they recover with ads, accounts, size caps and “premium” tiers. And while your book sits on their hardware, you're trusting they'll handle it well.

ebook.tools skips the server entirely. The conversion engine is delivered to your browser as code — the same way this page's images are — and runs on your machine. Serving code is essentially free at any scale, so there's nothing to charge for, and your files can't leak from a server they never reach.

Skeptical? Good. Load any tool page, turn off your wifi, and convert — it works exactly the same, because nothing needed the network. Read the full technical explanation.

Frequently asked questions

Is this really free?

Yes — every tool, with no signup, no watermarks, no daily limits and no “pro” nag. Running conversions in your browser instead of on servers means there’s no per-file cost for us to pass on to you.

Are my files uploaded anywhere?

No. The converter itself is downloaded to your browser and runs on your machine; your files are opened locally and never touch the network. You can switch off your wifi mid-session and keep converting — here’s how that works.

What formats are supported?

In: EPUB, MOBI, AZW3/KF8, PRC, FB2 (including .fb2.zip), DOCX, TXT, Markdown, CBZ and CBR. Out: EPUB, KEPUB for Kobo, CBZ and PDF — with AZW3 and MOBI output on the roadmap. Every file is identified by its actual contents, not its extension.

Does it work on my phone?

Yes — everything runs in the browser, so Android and iPhone work the same as desktop. Very large files (giant comic archives) are the one place phones can hit memory limits; if that happens, the tool will tell you rather than fail silently.

Is there a file size limit?

We impose none — there’s no upload cap because there’s no upload. The practical ceiling is your device’s memory, which comfortably handles typical books and multi-hundred-megabyte comic archives.