BZ2 Converter
FileFlip converts BZ2 files into 10 other formats entirely inside your browser, using libarchive compiled to WebAssembly. The BZ2 file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. There is no file-size limit and no account to create.
How do I convert a BZ2 file?#
- Drop your BZ2 file onto the converter at the top of this page, or click it to pick one from your computer.
- Choose the format you want out of it. FileFlip downloads the engine that conversion needs, once, and your browser caches it.
- Conversion starts the moment you pick the format, and the result is yours to download. The work happens in this tab, so nothing is uploaded and nothing is queued.
Is it safe to convert BZ2 files online?#
Yes, because nothing is uploaded. FileFlip converts BZ2 files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What happens to a BZ2 file#
FileFlip converts BZ2 into 10 formats with libarchive, all of it inside the browser tab. Each conversion below names the engine it uses, what it downloads, and exactly what that conversion keeps or drops.
| Category | Archives |
|---|---|
| File extension | .bz2 |
| FileFlip support | Read and written |
| Conversions available | 10 |
| Engines | libarchive |
| Downloaded to your browser | 1.0 MB on the first conversion, then cached |
What is a BZ2 file?#
A BZ2 file is a single stream compressed with Julian Seward's bzip2, which sorts each 100-900 KB block through a Burrows-Wheeler transform before Huffman coding it, trading compression speed for a smaller result than DEFLATE typically achieves.
Use BZ2 for text-heavy data where its tighter compression than gzip is worth the slower compression time.
Convert BZ2 to XZ when an even smaller archive is worth the additional compression time, or to GZ when compression speed matters more than ratio.
The BZ2 file format reference covers the specification, the programs that open one, and what each conversion keeps or drops.
BZ2 questions people ask#
Is bzip2 better than gzip?
bzip2 usually compresses noticeably smaller than gzip, especially on text, because its Burrows-Wheeler transform finds redundancy that DEFLATE misses. The cost is speed: bzip2 compression is markedly slower and needs more memory, sometimes cited at up to four times gzip's.
Can bzip2 hold more than one file?
No, bzip2 compresses a single file or stream just like gzip, so archiving several files as .bz2 means tarring them first into a .tar.bz2, or .tbz2.
Why does bzip2 compress in blocks?
bzip2 splits its input into blocks of 100 KB to 900 KB and runs the Burrows-Wheeler transform, move-to-front coding and Huffman coding on each block independently. That block structure is also what lets tools like pbzip2 compress a bzip2 file's blocks in parallel across multiple CPU cores.
Is bzip2 still worth using over xz?
For most jobs, no: xz built on LZMA2 usually compresses smaller than bzip2 and decompresses faster, which is why most Linux distributions moved their package compression from bzip2 to xz. bzip2 still shows up in older tooling and pipelines that were built around it.