EPUB to HTML Converter
Drop a DRM-free EPUB, get a single .html file you can read in any browser, host anywhere, or feed to indexing tools. Chapters are concatenated with breaks; images are inlined as data URIs so the file is self-contained.
Drop your EPUB file here
Converts to .html — stays on your device
Why convert EPUB to HTML?
- Reading a sideloaded EPUB in a browser when you don't want to install a reader app.
- Archiving a public-domain book from Project Gutenberg as a single self-contained HTML file.
- Hosting an open-source manual or technical book on the web from its EPUB master.
- Indexing the contents of an ebook with a search tool that takes HTML input.
- Reading on a Chromebook, school computer, or other locked-down machine where you can't install Calibre or an EPUB reader.
- Feeding ebook content to a screen reader, translation tool, or text-processing pipeline that prefers HTML over EPUB.
How our converter works
Your EPUB is unzipped client-side via fflate. We read META-INF/container.xml to find the OPF (package document), parse it to get the manifest and spine, and walk the spine in reading order. Each chapter's XHTML is parsed with the browser's DOMParser, and the body content is extracted. Image references are rewritten to inline data URIs so the resulting .html is fully self-contained — no external image folder needed. The output uses a clean default stylesheet (Georgia serif, ~42em column width). Conversion runs entirely in your browser.
Frequently asked questions
Is the output really a single self-contained file?
Yes. Images are encoded as data URIs and inlined directly into the HTML. CSS is in a `<style>` block. You can email the file, drop it on a thumb drive, or host it from a single URL — no companion folder needed.
Will the EPUB's custom CSS be preserved?
No — the output uses a clean default stylesheet. EPUB-internal CSS often references font files and selectors that wouldn't translate cleanly. If you need exact original styling, extract the EPUB manually (it's just a ZIP) and use the chapter XHTML files directly.
Will DRM-protected EPUBs work?
No. We work with DRM-free EPUBs only: Project Gutenberg, Standard Ebooks, Smashwords, your own writing, etc. We don't ship DRM-bypass tooling.
How big can the input be?
Up to a few hundred MB on desktop browsers, less on mobile. The data-URI inlining inflates the HTML to roughly the size of the original EPUB plus a base64 overhead (~33% for images).
Are my files uploaded?
No. fflate, DOMParser, and the file I/O all run as JavaScript on this page. Your books and manuscripts stay on your device.
About the EPUB format
EPUB is the open ebook standard maintained by the W3C — a ZIP container of XHTML chapters, CSS, fonts, images, and a package manifest (OPF) declaring the reading order. HTML is the format every browser reads natively, and a single self-contained .html (with images inlined as data URIs) is one of the most portable archival forms there is — it works offline, on any OS, with no companion files. Converting EPUB→HTML is what you do when you want a book that's readable in a browser, indexable by search tools, hostable on the web, or simply readable on a machine where you can't install a dedicated EPUB reader. The conversion preserves text and structure exactly; the original CSS is replaced with a clean default for legibility.