HTMLZ to EPUB Converter
Convert a zipped HTML (HTMLZ) archive to EPUB online. Free, private, and processed entirely in memory.
Complete the security check to begin
About Converting HTMLZ to EPUB
HTMLZ is a deliberately simple format: a zip containing a single HTML file plus its images and stylesheet. It exists as an interchange and archival format rather than a reading one — a way to keep a document as plain, inspectable HTML without scattering it across a folder of loose files. It is the format people reach for when they want something durable and readable by hand, and the format they then need to convert when they actually want to read it on a device.
That conversion is more than a rename. An EPUB is also a zip of HTML, but it is a structured package: it needs a mimetype declaration, a META-INF container pointing to a package document, an OPF manifest listing every resource, and a navigation document for the table of contents. This converter builds all of that, splits a single long HTML file into sensible sections, and rewrites the internal links so they still resolve. The result is a valid EPUB that readers will accept, rather than a renamed archive they reject.
Common use cases
- Turning an archived HTML document into a book you can read on an e-reader or phone
- Publishing content written or exported as plain HTML in a format readers accept
- Converting a saved article, manual or report into a proper paginated book
- Moving a document out of an archival format into a distributable one
- Adding structure and a table of contents to a single long HTML file
Tips for best results
- Nothing inside an HTMLZ is ever fetched from the internet. Remote images, tracking pixels, external stylesheets and scripts referenced by the HTML are not loaded — the conversion runs in a sandbox with no network access at all. For a format that carries arbitrary HTML, that is the security property that matters most.
- Headings determine the structure. The converter uses the HTML heading levels to split the document into chapters and build navigation, so a file with proper h1 and h2 tags converts into a well-organised book while a flat one becomes a single chapter.
- Images have to be inside the archive. Anything referenced by an external URL will simply be absent from the EPUB, because nothing is downloaded during conversion.
- Convert to PDF instead if the layout is fixed and matters — a form, an invoice, anything designed to specific dimensions. EPUB reflows, which serves prose well and precise layout badly.
How to Convert HTMLZ to EPUB Online
Converting HTMLZ to EPUB with PrivConvert takes three quick steps and no software to install. What you gain with EPUB: reflowable text for any screen.
Drag and drop your file into the upload area, click to browse your device, or paste a URL to a file hosted online. You can upload files up to 250 MB and batch convert up to 20 files at once.
Once uploaded, the conversion from HTMLZ to EPUB starts automatically. The process runs entirely in an isolated environment - your data never leaves the secure pipeline.
Your converted file is ready instantly. Click the download button to save it to your device. The file is deleted from memory immediately after download.
Why convert HTMLZ to EPUB with PrivConvert?
PrivConvert turns your HTMLZ into EPUB without ever storing, logging or sharing it. Here is what that looks like in practice:
We never keep a copy. Once your EPUB is delivered, both the original and the result are gone — there is nothing left to leak or misuse.
Every conversion runs in its own locked-down process with no network access, so files can never leak or interfere with one another.
Your files are handled entirely by automated code. No staff, partner or AI model ever reads, stores or trains on your data.
Files are processed in volatile memory (RAM) and purged the instant your download is ready — nothing is ever written to disk, cached or backed up.
HTMLZ vs EPUB - Format Comparison
| Feature | HTMLZ | EPUB |
|---|---|---|
| File extension | .htmlz | .epub |
| Supported by PrivConvert | Yes (as input) | Yes (as output) |
| Privacy-safe conversion | In-memory, zero storage | |
| Max file size | 250 MB per file | |
| Batch support | Up to 20 files simultaneously | |
Built for people who value their privacy
From one-off files to daily batches, thousands of people rely on PrivConvert precisely because it keeps nothing once the job is done.