Just Tool It
Just Tool It / Ebook Converter
On-device — nothing uploaded

Ebook Converter

Drop an EPUB, HTML, TXT or FB2 file and convert between them. Zero dependencies — the browser does the unzipping, parsing and re-packing.

Drop an ebook here

or browse from your device — EPUB, HTML, TXT, FB2

Convert ebooks without uploading

Most online ebook converters upload your file to a Calibre-driven server, run a conversion there, and email you a download link. That works, but it puts a copy of your reading list on infrastructure you don't control. Just Tool It does the conversion right here — the browser's built-in DecompressionStream unzips the EPUB, DOMParser reads the XHTML, and a small writer packs it back as the format you choose. The original file never leaves the tab.

Supported formats

  • EPUB — the open ebook standard. ZIP of XHTML files. Round-trips cleanly.
  • HTML — single-page output of the whole book, useful for sending to a Read-it-later tool or printing.
  • TXT — plain text, paragraphs preserved. Great for word counts, full-text search, or moving content into a note app.
  • FB2 — FictionBook XML, popular for Russian-language readers and many e-ink devices.

How to use

  1. Drop an ebook onto the upload area, or click to browse.
  2. Pick the target format. EPUB and FB2 keep structure; HTML and TXT collapse to flowing text.
  3. (Optional) Edit title and author. Used for the EPUB / FB2 metadata block. Auto-detected when possible.
  4. Click Convert, then Download.

Frequently asked questions

Why no MOBI or AZW3 (Kindle) support?
MOBI and AZW3 are Amazon's proprietary formats. There is no maintained, working JavaScript encoder for them — Amazon's own KindleGen is the only reliable writer and it doesn't run in a browser. Even Calibre delegates to a native binary for these. A trustworthy client-side converter for MOBI/AZW3 would require shipping many megabytes of code that may not work reliably. We prefer to be honest about the limit. Convert to EPUB here, then use a desktop tool (Calibre, Kindle Previewer) for the final MOBI step if you need one.
Why no LIT or LRF support?
LIT (Microsoft Reader) and LRF (Sony) have been dead for over a decade — no modern reader uses them. There are no maintained JS libraries for either. If you have one of these files, convert it elsewhere first and bring the EPUB or TXT result back here.
Is my book uploaded anywhere?
No. The file is processed inside this tab using the browser's built-in ZIP decompression, XML/HTML parser, and ZIP encoder. Disconnect from the internet after the page loads and the converter still works.
Will formatting be preserved?
Headings, paragraphs and basic emphasis are preserved across EPUB → HTML and EPUB → FB2. TXT output drops formatting by design. Complex layouts (drop caps, sidebars, embedded fonts) flow as plain text. Tick "Strip images" to drop embedded images when you want the smallest possible output.
What about PDF?
PDF ebook conversion is handled by our Document Converter, which loads pdf.js and jsPDF on demand. We keep this Ebook tool focused on the open ebook family so it stays dependency-free.