HTMLZ is Calibre's zipped-HTML ebook format: the web page plus its images in one portable archive — a "web-to-ebook" snapshot.
Typical use: Convert HTMLZ snapshots back to plain text or EPUB for e-readers.
About the HTMLZ format
HTMLZ is Calibre's answer to "save the whole page": the HTML document, its images and its stylesheet zipped into one file. It is a web snapshot that e-reader pipelines can treat as a book — a format born from the era of clipping articles for offline reading.
The archive opens in the browser, the main HTML feeds the chapter pipeline, and text or EPUB comes out with images dropped or embedded depending on the target.
Strengths
- ✓ Complete page snapshot in one file
- ✓ Calibre-native round-trip
- ✓ Easy to inspect (it is just a zip)
Limitations
- ✗ No reader displays it directly
- ✗ Styles rarely survive conversion
- ✗ Multi-file URLs can break image paths
- Structure
- Zip of index.html + assets
- Types / schema
- HTML in a container
- Compatibility
- Calibre, Pandoc
- Best for
- Web clipping for e-readers
Convert HTMLZ to…
4 direct directions, sorted A–Z; 🔥 marks popular targets.
Frequently asked questions
What is a HTMLZ file?
HTMLZ is Calibre's zipped-HTML ebook format: the web page plus its images in one portable archive — a "web-to-ebook" snapshot.
How do I convert HTMLZ files online?
Pick a target format from the "Convert HTMLZ to…" list below, drop your file and hit convert. Everything runs in your browser — no install, no upload, no watermark, no limits.
Is it safe to convert HTMLZ files here?
Yes. Every conversion is performed by your own device inside the browser — files never leave for a server, and the page keeps working even offline.
Which formats can HTMLZ convert to?
This page lists all 4 directions across documents, images, audio, video, spreadsheets and archives — each one is its own free converter page.