TGZ to TZ2 Converter

How to Convert TGZ to TZ2 Online

1. Upload Your TGZ File: Drag and drop or click "+ Add Files" to select one or more .tgz archives from your computer. Batch upload is supported — queue several archives and convert them in one pass.
2. Pick Single Archive vs Individual Archives: Default is "Single Archive" — every uploaded .tgz is decompressed and re-bundled into one combined .tz2. Switch to "Individual Archives" to produce one .tz2 per input .tgz (useful when you want to keep release tarballs separate).
3. Confirm the Output Extension: TZ2 is locked as the target (it's the short form of .tar.bz2 — same archive, shorter filename). No quality slider is needed because bzip2 uses a fixed block-sorting algorithm; the converter applies bzip2's standard 900 KB block size for best compression.
4. Convert and Download: Click "Convert." Files are decompressed from gzip, the underlying tar is recompressed with bzip2, and the resulting .tz2 is offered as a direct download. No sign-up, no watermark, no installation.

Why Convert TGZ to TZ2?

A .tgz file is a tar archive compressed with gzip; a .tz2 is the same tar archive compressed with bzip2. The container is identical — only the outer compression layer changes. Bzip2 typically produces files 10-15% smaller than gzip on the same input, and up to ~30% smaller on text-heavy data such as source code, logs, or JSON dumps. The tradeoff is CPU time: bzip2 compresses and decompresses noticeably slower than gzip, so the switch is worth it when storage or bandwidth costs more than a few extra seconds of unpacking.

• Shrink long-term backups — A nightly database dump, weekly log roll, or monthly source-tree snapshot stays online for months or years. Trading a few seconds of CPU for 15% smaller files compounds across hundreds of retained archives.
• Cut bandwidth on slow links — Mirror-server admins, embedded-Linux distributors, and anyone shipping rootfs tarballs over LTE or satellite links pay per megabyte. Re-compressing release tarballs to .tar.bz2 is a common pre-publish step.
• Match upstream packaging conventions — Many GNU projects (coreutils, gcc, glibc), older KDE source releases, and FreeBSD ports historically ship .tar.bz2. Converting a third-party .tgz to .tz2 keeps your local mirror consistent.
• Use the .tz2 short form on legacy filesystems — Some older Windows tooling and a few archaic FTP clients truncate or mishandle double extensions. .tz2 (and .tbz2, .tbz, .tb2) are documented single-extension aliases for .tar.bz2.
• Compress source-code repositories tighter — Bzip2's Burrows-Wheeler block-sorting handles repetitive text (similar function names, common keywords, repeated copyright headers) better than gzip's LZ77+Huffman. Source dumps and CSV exports often shrink the most.

If you need maximum compression instead of bzip2, use TGZ to TAR.XZ — xz/LZMA2 typically beats bzip2 by another 15-25%. To go the other way, see TZ2 to TGZ.

TGZ vs TZ2 — Format Comparison

Bzip2 Block Size Quick Guide

Bzip2 has a single tunable: block size, from -1 (100 KB) to -9 (900 KB). The converter uses the default -9 because it produces the smallest output for almost all inputs.

Unlike gzip and xz, bzip2's "level" controls block size, not algorithm aggressiveness. Higher = bigger blocks = better compression of files larger than the block, but no benefit for files that already fit in a smaller block.

Frequently Asked Questions

Is .tz2 the same thing as .tar.bz2?

Yes. .tz2 is a documented short-form extension for a tar archive compressed with bzip2. Other aliases for the same content are .tbz2, .tbz, and .tb2. The bytes inside the file are identical — only the filename differs. You can rename .tz2 to .tar.bz2 and any extractor will still open it.

How much smaller will my .tz2 be compared to the .tgz?

For most inputs, expect a 10-15% size reduction. Text-heavy archives (source code, logs, CSV, JSON, XML) often shrink 20-30%. Archives that are already mostly compressed data (JPEGs, MP4s, pre-zipped files) will see little or no improvement, since both gzip and bzip2 struggle to compress already-compressed bytes.

Why is bzip2 decompression so much slower than gzip?

Bzip2 uses the Burrows-Wheeler transform, which requires sorting an entire 900 KB block before any output bytes can be produced. Gzip's DEFLATE is a streaming LZ77+Huffman algorithm that emits bytes as it goes. The compression ratio gain costs roughly 2-3x decompression wall time on commodity CPUs — usually still under a second for archives below 100 MB.

Will the contents of the tar archive change?

No. Both .tgz and .tz2 wrap the same POSIX ustar (or GNU tar) container. File names, permissions, ownership, mtimes, symlinks, and directory structure are preserved exactly. Only the outer compression layer is rewritten.

Can my Mac or Windows PC open a .tz2 file?

Yes on both. macOS and every modern Linux distro have tar with built-in bzip2 support (tar -xjf file.tz2). Windows 10 (build 17063, Dec 2017) and Windows 11 ship Microsoft's bsdtar as tar.exe, which also handles bzip2. Third-party tools like 7-Zip, PeaZip, and WinRAR have supported .tar.bz2/.tz2 for over a decade.

Should I use .tz2 or .tar.xz for new archives?

If size is the only goal, prefer .tar.xz — LZMA2 typically beats bzip2 by another 15-25% on the same data, with comparable decompression speed. Bzip2 still wins when you need maximum compatibility with very old Linux/Unix systems (bzip2 has been standard since the late 1990s; xz tooling spread mostly after 2009) or when minimizing decompression memory matters.

Does converting twice (TGZ → TZ2 → TGZ) lose data?

No. Both gzip and bzip2 are lossless compressors. The intermediate tar stream is bit-identical at every stage, so round-tripping reproduces the original archive byte-for-byte. The only thing that may differ is the wrapper's mtime header, which records when the compression happened — not file contents.

Why does my .tz2 still look big after conversion?

The most common cause is an archive full of already-compressed payloads — .jpg, .png, .mp4, .mp3, .zip, .docx, or .apk files. Both gzip and bzip2 give up early on high-entropy data. If your archive is mostly media, consider compressing the individual files first or switching to a media-aware container.

Is there a file size limit on this converter?

The converter handles archives up to several gigabytes; very large jobs may time out depending on browser memory. For archives over ~2 GB, command-line tar is faster and more reliable: tar -xzf input.tgz && tar -cjf output.tz2 <extracted-dir>.