Extract .BZ2 Files Online
(No Size Limits)

A .bz2 file holds one compressed file and nothing else. Bzip2 has no concept of folders or multiple entries, so backup.sql.bz2 decompresses to exactly one backup.sql. If you were expecting a folder, the file you want is probably .tar.bz2, where TAR does the bundling first.

Why bzip2 still exists

Bzip2 works differently from gzip. It sorts blocks of data with the Burrows-Wheeler transform before Huffman coding them, which produces noticeably smaller files than gzip at the cost of being slower in both directions. For years that was the sensible trade for anything distributed once and downloaded often.

XZ and Zstandard have since taken both ends of that trade, XZ compressing harder and Zstandard decompressing far faster, so new projects rarely choose bzip2. It remains common because a great deal of existing software, scientific data and older Linux packaging was published in it and never re-encoded.

Why this one was hard to build

BZ2 routed through the bundled build of libarchive.js, whose only entry point copies the entire archive into the WebAssembly heap before doing anything. That imposed a 300 MB ceiling on a page that advertises no size limits.

The callback API that would allow streaming was compiled into that build but never exported, and every prebuilt libarchive binding published to npm takes the archive as a single Uint8Array. None of them can stream, so none could fix it.

libarchive is therefore built from source here with both halves exposed. Input arrives through archive_read_set_read_callback and its seek and skip counterparts, answered from a sliding window over the file, so the archive is never resident in memory. Output returns through archive_read_data_block one chunk at a time and is written straight to disk. Memory stays flat in both directions regardless of file size.

Doing it from a terminal instead

To decompress a single .bz2 file, keeping the original:

bunzip2 -k archive.bz2

For a .tar.bz2, GNU tar detects the compression on its own:

tar -xf archive.tar.bz2

What does not work

Multi-volume archives split across several files are not supported, and neither is encrypted 7z. Bzip2 has no encryption of its own, so a password-protected .bz2 is really an encrypted container holding one, and that outer layer has to come off first.