How do I convert an EPUB to HTML using Calibre?

In the Calibre GUI: add the EPUB, right-click → Convert books → Convert individually, set Output format to HTML or HTMLZ in the top-right dropdown, click OK. From the command line: run 'ebook-convert book.epub book.html'. HTMLZ produces a ZIP file with HTML + CSS + images, which is more portable than a bare HTML file.

Can Pandoc convert EPUB to HTML?

Yes. Run: pandoc book.epub -o book.html --standalone. The --standalone flag wraps the output in a complete HTML document. For EPUBs with images, add --extract-media=./media to save images to a subfolder. Pandoc merges all EPUB chapters into a single HTML file.

Can I read an EPUB file directly in a browser?

Not natively — browsers don't support the EPUB format. You need to either convert the EPUB to HTML first (using Calibre or Pandoc), install a browser extension like EPUBReader for Firefox, or use an online EPUB viewer. Once converted to HTML, the file opens in any browser with double-click or drag-and-drop.

What is the difference between HTML and HTMLZ output in Calibre?

HTML output from Calibre produces a folder with separate .html files per chapter plus CSS and image files. HTMLZ is a single ZIP file containing the same HTML + CSS + images — easier to share as one file. For reading in a browser, HTML is simpler; for archiving or sharing, HTMLZ keeps everything together.

How to Convert EPUB to HTML (Online, Calibre, and Pandoc)

Converting EPUB to HTML lets you read ebooks in any browser, extract content for web publishing, or process ebook text programmatically. Here are three reliable methods.

Why Convert EPUB to HTML?

Browser reading: HTML files open in any browser — no EPUB reader required. Useful for sharing with non-readers or for reading on devices without an EPUB app.
Content extraction: Converting to HTML gives you access to the raw text and structure for editing, republishing, or archiving.
Web publishing: If you wrote a book and want to publish chapters on a website, EPUB-to-HTML is the first step.
Programmatic processing: HTML is easier to parse with standard web scraping tools than the ZIP-based EPUB format.

Method 1: Calibre (Desktop, Free)

Calibre's ebook-convert command converts EPUB to a single HTML file or a set of HTML files:

ebook-convert book.epub book.html

Or for multiple chapter files:

ebook-convert book.epub book/ --output-dir book/

In the Calibre GUI:

Add the EPUB to your Calibre library.
Right-click → Convert books → Convert individually.
Set Output format to HTMLZ or HTML in the top-right dropdown.
Click OK. Calibre converts the file and saves to your library folder.

HTMLZ is a ZIP file containing HTML + CSS + images — more portable than a bare HTML file with external assets.

Method 2: Pandoc (Command Line)

Pandoc can convert EPUB directly to HTML in one command:

pandoc book.epub -o book.html --standalone

The --standalone flag produces a complete HTML file with <html>, <head>, and <body> tags rather than a fragment. For multi-chapter EPUBs, Pandoc merges all chapters into one HTML file.

To preserve images, use --extract-media:

pandoc book.epub -o book.html --standalone --extract-media=./media

This saves all embedded images to a media/ subfolder and links to them in the HTML.

Method 3: Online Converters

Several online tools convert EPUB to HTML without installing software:

CloudConvert: Supports EPUB → HTML. Free tier allows a limited number of conversions per day. Output is a ZIP containing HTML + assets.
Zamzar: Supports EPUB → HTML. Free tier requires email delivery. Output quality varies.
epub2go.com: Converts EPUB to a browsable web view directly in the browser — no download needed for reading.

What the Output HTML Looks Like

When converting from EPUB to HTML, each chapter in the EPUB (a separate XHTML file) typically becomes:

Calibre: A separate .html file per chapter, or one merged HTML file, depending on output settings.
Pandoc: One merged HTML file with all chapters concatenated, preserving heading hierarchy.
Online tools: Usually a ZIP with one HTML file per chapter plus a CSS stylesheet and image folder.

Reading the HTML Output in a Browser

Once converted, open the HTML file in any browser (double-click or drag into a browser tab). For the best reading experience:

Use Firefox's Reader View (F9) to strip navigation and render clean text.
Chrome's reading mode (available in Flags) provides similar clean rendering.
On mobile, use Kiwi Browser (Android) or open the file via Files app in Safari (iOS).

Need to go the other direction — PDF to EPUB? toolkit.bot converts with heading detection and OCR.

Convert PDF to EPUB →