FB2 Won't Open? Convert to HTMLZ Instantly
Fast, instant FB2 to HTMLZ conversion. No signup required. Just drop your .fb2 file and get .htmlz in seconds.
Batch Settings
About FB2 to HTMLZ Conversion
Dealing with a FB2 file that won't open on your device? You're not alone — FB2 compatibility issues are one of the most common reasons people search for a file converter. FB2 (FictionBook) is an XML-based e-book format popular in Russia and Eastern Europe.
The fix is simple: convert your FB2 to HTMLZ. HTMLZ is a widely used file format. This conversion lets you convert between formats quickly, solving the problem in seconds rather than hours of troubleshooting.
Converting FB2 to HTMLZ maintains high quality with CocoConvert's optimised encoder settings.
CocoConvert processes your FB2 file on secure servers in Germany — upload, convert, download. Your files are encrypted via TLS and automatically deleted within 24 hours. No account needed, no software to install, and it works on any device with a browser.
This conversion is ideal when you When you need a HTMLZ file.
The conversion engine behind CocoConvert uses FFmpeg, Sharp, and qpdf — the same open-source libraries trusted by Netflix, YouTube, and enterprise platforms. Pro users can batch convert up to 100 files at once.
How to Convert FB2 to HTMLZ
- 1
Add your FB2 file
Drag and drop your .fb2 file into the converter, or tap "Browse" to pick it from your device. Multiple files are supported for batch processing.
- 2
Pick HTMLZ output
Select .htmlz as the target format. CocoConvert automatically applies the best quality settings for this conversion.
- 3
Start conversion
Hit the Convert button. The ebook engine processes your file server-side — no CPU drain on your device.
- 4
Save your file
Once done, download your .htmlz file. For batch jobs, download all at once as a zip.
What Happens When You Convert FB2 to HTMLZ
Your FB2 file is decoded and re-encoded as HTMLZ.
Your FB2 file is uploaded and validated
The file is decoded (parsed into its raw data)
The data is re-encoded in HTMLZ format
The converted file is ready for download
Format Comparison
FB2
.fb2 file
| Extension | .fb2 |
| MIME Type | application/x-fictionbook+xml |
| Category | eBook |
HTMLZ
.htmlz file
| Extension | .htmlz |
| MIME Type | application/zip |
| Category | eBook |
Should You Convert FB2 to HTMLZ?
When to Convert
- ✓When you need a HTMLZ file
Frequently Asked Questions
Why won't my FB2 file open?
FB2 files may not open if your device lacks the right codec or application. Converting to HTMLZ — a more widely supported format — usually resolves this. HTMLZ is a widely used file format.
Is it safe to convert FB2 to HTMLZ online?
Yes. CocoConvert encrypts your file via TLS, processes it on isolated servers in Germany, and permanently deletes it within 24 hours. Your files are never shared or analysed.
Will I lose quality converting FB2 to HTMLZ?
Converting FB2 to HTMLZ maintains high quality with CocoConvert's optimised encoder settings. CocoConvert uses high-quality encoder defaults to preserve as much fidelity as possible.
How large can my FB2 file be?
Free users can convert files up to 250 MB each. Pro users get a 5 GB limit per file, and Business API users have custom limits.
Can I convert FB2 to HTMLZ on my phone?
Absolutely. CocoConvert works in any modern browser — iOS Safari, Android Chrome, and all desktop browsers. No app required.
Versions are pinned in our worker Dockerfile and re-built via CI on every change.