TAR.GZ to TZ2 Converter

How to Convert TAR.GZ to TZ2 Online

1. Upload Your TAR.GZ File: Drag and drop, or click "+ Add Files" to pick .tar.gz / .tgz archives from your computer. Multiple archives are supported in one batch.
2. Pick TZ2 as the Output: TZ2 is already selected — it's the same content as .tar.bz2 repacked with bzip2 compression instead of gzip. The output extension .tz2 is one of several short forms for tar+bzip2 (alongside .tbz2, .tbz, and .tb2).
3. Choose Single Archive or Individual Archives (Optional): Under "Combine?" pick Single Archive to merge every uploaded .tar.gz into one combined .tz2, or Individual Archives to produce one .tz2 per input file (the default when uploading multiple archives).
4. Convert and Download: Click Convert. The server re-streams the gzip-encoded tar through bzip2, then sends back the .tz2. Files are removed from the server after the session ends — no sign-up, no watermark.

Why Convert TAR.GZ to TZ2?

.tar.gz and .tz2 package the same underlying tar stream, but they apply different compression algorithms. Gzip (DEFLATE, 1992) is fast but leaves bytes on the table. Bzip2 (Julian Seward, first released August 1997) uses the Burrows–Wheeler transform with 100–900 KB block sorting plus Huffman coding, and typically compresses ~10–20% smaller on text-heavy payloads. The trade-off is CPU: bzip2 compresses roughly 1.5× slower and decompresses ~4× slower than gzip on the same input (rootusers benchmark on the Linux kernel source).

• Archive size matters more than decompress speed — Long-term backups, off-site cold storage, and one-time distribution of source tarballs all favor bzip2's tighter ratio. The few extra CPU seconds on extract are paid only when someone actually unpacks the archive.
• Source-code releases and Linux distro tarballs — Many upstream projects (the Linux kernel itself, GNU coreutils, ImageMagick) historically shipped both .tar.gz and .tar.bz2 so users could pick. Re-encoding to .tz2 matches that convention when re-mirroring.
• Text-heavy payloads — logs, CSV, SQL dumps — Bzip2's block sorting excels on repeating patterns. A 1 GB syslog or PostgreSQL dump that compresses to ~120 MB with gzip often lands around ~95 MB with bzip2.
• Hand-off to systems that prefer .tz2 / .tbz2 — Older Slackware packages, some BSD ports trees, and a few build pipelines key off the .tz2 short form. Converting locally avoids a rename step on the receiving side.
• Reducing bandwidth on a cold mirror — If a mirror serves an archive that's downloaded once a quarter but stored forever, bzip2 wins on both bandwidth and storage at the cost of one extra second of client CPU per MB.

TAR.GZ vs TZ2 — Format Comparison

Gzip vs Bzip2 — Quick Compression Reference

Numbers below are from the rootusers benchmark compressing 580 MB of Linux kernel source at max level (-9), useful as a directional reference rather than exact ratios for your data.

Frequently Asked Questions

Is .tz2 the same as .tar.bz2?

Yes — the bytes are identical. .tz2, .tbz2, .tbz, and .tb2 are all single-extension short forms for a tar archive compressed with bzip2, exactly equivalent to the double-extension .tar.bz2. The single-extension forms exist mostly because legacy filesystems (FAT, ISO 9660 Level 1) and some Windows tools handled double extensions poorly. You can rename a .tar.bz2 to .tz2 and extract it with tar -xjf on Linux/macOS, or with 7-Zip, PeaZip, or WinRAR on Windows.

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

For source code, plain text, logs, and SQL dumps, expect roughly 10–20% smaller. For already-compressed payloads inside the tar (JPEGs, PNGs, MP4s, pre-zipped files), the savings drop to near zero because both gzip and bzip2 struggle to compress data that's already been deduplicated. A .tar.gz of JPEGs converted to .tz2 may even grow slightly because of bzip2's slightly larger headers.

Why is the conversion slower than I expected?

The server has to decompress your .tar.gz (fast — gzip decompresses around 96 MB/s on a modern core) and then re-compress with bzip2 (slow — bzip2 compresses around 7 MB/s at level 9). The bzip2 step dominates. A 1 GB tarball typically takes 2–3 minutes to re-encode on a single core. If you're doing this locally, pbzip2 parallelizes across cores and can cut wall time by ~Ncores.

Will Linux/macOS extract .tz2 automatically?

GNU tar on Linux auto-detects compression from magic bytes since the late 2000s, so tar -xf archive.tz2 works without specifying -j. BSD tar (the default on macOS) also auto-detects bzip2. Older systems may need the explicit flag: tar -xjf archive.tz2. The j flag specifically invokes bzip2, mirroring -z for gzip and -J for xz.

What about .tar.xz? Isn't that better than .tz2?

For pure compression ratio, yes — xz (LZMA2) typically beats bzip2 by another 10–15% and is now the standard for Linux kernel source releases. But xz uses much more memory at decompress (up to ~64 MB for level 6, vs ~3.7 MB for bzip2) and is slower to encode. .tz2 remains useful when targets have tight memory budgets (embedded systems, older NAS firmware) or you need the wide compatibility of bzip2, which has been in every POSIX-ish toolchain since the early 2000s. If memory and toolchain aren't constraints, convert to TAR.XZ for the tightest archive.

Can I extract just one file from the .tz2 without unpacking everything?

Yes, but it's slower than with .tar.gz. Run tar -xjf archive.tz2 path/inside/archive. Tar has to bzip2-decompress sequentially from the start of the stream until it finds your file, because bzip2 doesn't have a random-access index. For frequent partial extracts on large archives, gzip is actually a better choice, or use a format with an index (.zip, .7z).

Does bzip2 add any integrity check?

Each bzip2 block carries a 32-bit CRC, and the stream ends with a combined CRC of all blocks. If a .tz2 is truncated or corrupted, tar reports a CRC mismatch and refuses to extract the bad block. This is comparable to gzip's CRC-32 footer. Neither format authenticates — for tamper detection, sign the archive with GPG or pair it with a SHA-256 checksum.

What if I just want to look inside the .tar.gz first?

If you only need to see what's in the archive (or pull a few files), skip the re-compression and use Extract TAR.GZ to unpack it directly. If you actually need to keep an archived form but want gzip's faster extract characteristics retained, leave it as .tar.gz — converting just to convert wastes CPU. The conversion to .tz2 only pays off when you'll store or transmit the archive and want the smaller size.

Will the file timestamps and permissions survive the conversion?

Yes. The tar layer carries POSIX file metadata (owner, group, mode bits, mtime), and that layer is unchanged — only the outer compression wrapper is swapped from gzip to bzip2. Symlinks, hardlinks, sparse files, and (with --xattrs) extended attributes all pass through unchanged. If you compare tar -tvf output before and after, you should see identical entries.

Need a sibling format instead? TAR.GZ to TAR.BZ2 produces the long-form double extension instead of .tz2, TAR.GZ to TAR.XZ gives the tightest compression at the cost of decompress memory, or use Extract TAR.GZ to unpack without re-archiving.