How to Convert TB2 to 7Z Online
- Upload Your TB2 File: Drag and drop your
.tb2/.tbz2archive onto the drop zone, or click "+ Add Files" to browse. Batch upload is supported — queue multiple archives and convert them in one pass. - Pick the Output Format: 7Z is already selected. Switch to a different container from the format selector if you also need TB2 to ZIP, TB2 to RAR, or TB2 to TAR.
- Choose Combine? (Optional): Default is Single Archive — every uploaded file is packed into one
.7z. Switch to Individual Archives to produce a separate.7zfor each input TB2, useful when you want to keep release builds or per-project backups isolated. - Convert and Download: Click "Convert". xConvert decompresses the bzip2 layer, unpacks the TAR, then re-compresses with LZMA2 inside the 7z container. No sign-up, no watermark, no email required.
Why Convert TB2 to 7Z?
A .tb2 file (also spelled .tbz2 or .tar.bz2) is a TAR archive compressed with bzip2 — the dominant "ship a Linux source tarball" format from the late 1990s and 2000s. The 7z format, introduced by Igor Pavlov with 7-Zip in 1999, uses LZMA2 by default and typically delivers a tighter ratio on text and source code than bzip2's Burrows-Wheeler Transform pipeline. Converting trades some encoder CPU time for smaller files, AES-256 encryption support, and a single-file Windows-friendly container.
- Shrink long-term backups. LZMA2 with a large dictionary often beats bzip2 by 10-25% on source trees, log archives, and database dumps. Old
.tb2snapshots from a CI server can re-pack to.7zand free real disk space. - Email or share on Windows without explaining tar. Windows 11 added native
.tar.bz2extraction in 2023, but many corporate Windows 10 machines still need 7-Zip or WinRAR to open a.tb2. A.7zopens the same way on every Windows box with 7-Zip installed and is one file instead of "tar inside bzip2." - Add password protection.
.tar.bz2has no native encryption — you'd have to wrap it in GPG. 7z supports AES-256 with SHA-256 key derivation, encrypts file contents and (optionally) the filename listing, and is widely supported by 7-Zip, PeaZip, Keka, and The Unarchiver. - Modernize legacy Linux distributions. Old kernel sources, ports trees, and academic datasets that ship as
.tb2can be re-archived to.7zfor offline storage. If you need to preserve the TAR layer's POSIX permissions instead, route through TB2 to TAR.XZ for streaming xz with full Unix metadata. - Faster random access for browsing. 7z stores a central directory and per-file metadata, so a GUI tool can list and extract a single file without scanning the whole stream. With
.tb2the bzip2 layer is solid — listing one file still pays the full decompression cost. - Cross-tool consistency. 7-Zip is shipped with most Linux package managers (
p7zip), is bundled with macOS through Homebrew/Keka, and runs natively on Windows. A.7zdeliverable is the closest thing to a universal "compressed bundle" today.
TB2 (tar.bz2) vs 7Z — Format Comparison
| Property | TB2 (tar.bz2) | 7Z |
|---|---|---|
| Year introduced | bzip2 released August 1997 (Julian Seward); TAR predates 1979 | 1999 (Igor Pavlov, 7-Zip) |
| Default compression algorithm | Burrows-Wheeler Transform + RLE + Huffman (bzip2) | LZMA2 (configurable: LZMA, LZMA2, PPMd, BZip2) |
| Typical ratio on source/text | Baseline | ~10-25% smaller than bzip2 with LZMA2 |
| Block / dictionary size | 100-900 KB bzip2 block | Up to 4 GB LZMA dictionary |
| Encryption | None native (requires GPG or external) | AES-256 with SHA-256 key derivation |
| Filename/directory metadata | TAR layer preserves POSIX permissions, owners, symlinks | Stored in 7z header; permissions limited vs TAR |
| Random access to one file | No — bzip2 stream is solid, must decompress to seek | Yes — central directory + per-file offsets |
| Native Windows support | Added in Windows 11 (2023); older Windows needs 7-Zip/WinRAR | Requires 7-Zip / PeaZip / WinRAR — not in Windows Explorer |
| Native macOS support | Yes (tar -xjf built in) |
Requires Keka / The Unarchiver / Homebrew p7zip |
| Linux | Standard everywhere | p7zip package, in nearly every distro repo |
| Typical use today | Source tarballs, Linux/BSD distribution | General-purpose Windows-friendly distribution, encrypted bundles |
LZMA2 Compression Level Quick Guide
7-Zip exposes nine levels (-mx0 through -mx9). xConvert's server uses balanced defaults; if you re-compress locally afterward, this is what each level means:
| Level | Name | Dictionary | Use when |
|---|---|---|---|
| 0 | Store | — | Already-compressed payloads (JPEG, MP4, existing .7z) — no further squeeze |
| 1 | Fastest | 64 KB | You need speed, ratio doesn't matter (CI scratch) |
| 3 | Fast | 1 MB | Quick day-to-day archiving |
| 5 | Normal | 16 MB | 7-Zip GUI default, balanced |
| 7 | Maximum | 32 MB | Distribution downloads, long-term backups |
| 9 | Ultra | 64 MB (or larger) | Smallest possible file, RAM-hungry, slowest |
Higher levels mostly help large text-like data. Level 9 on a folder of MP4 or JPEG files saves almost nothing.
Frequently Asked Questions
Why is my converted 7Z smaller than the original TB2?
LZMA2 typically compresses source code, text, logs, and uncompressed binaries 10-25% tighter than bzip2 on the same input. The 7z container also drops the bzip2 framing overhead. Already-compressed data inside the archive (JPEGs, MP4s, prior .gz files) won't shrink much regardless of algorithm.
Will file permissions, symlinks, and owner IDs survive the conversion?
The TAR layer inside your .tb2 stores POSIX permissions, ownership, symlinks, and timestamps. When converting to a flat .7z, the 7z container preserves filenames, timestamps, and basic Windows-style attributes but does not carry full POSIX UID/GID/symlink semantics. If you need bit-exact permissions for a Linux deployment, keep the TAR inside (TAR-then-7Z) or stay on .tb2 / .tar.xz.
What opens a 7Z file after conversion?
7-Zip on Windows and Linux, Keka or The Unarchiver on macOS, PeaZip cross-platform, and WinRAR on Windows. Most Linux distros ship p7zip (sudo apt install p7zip-full on Debian/Ubuntu). Windows 11 added native handling for many archive formats in 2023, but 7-Zip is still the most reliable across versions.
Can I add a password to the 7Z output?
The standard xConvert conversion produces an unencrypted 7z. If you need AES-256 encryption, re-archive locally with 7-Zip (7z a -p -mhe=on archive.7z files) — -mhe=on also encrypts the filename listing so a casual viewer can't even see what's inside.
Is TB2 the same as TBZ2 or tar.bz2?
Yes — all three refer to the same format: a TAR archive compressed with bzip2. .tar.bz2 is the canonical double extension; .tb2 and .tbz2 are short forms used on filesystems that don't tolerate dotted extensions or on Windows where Explorer truncates at the first dot. Some tools also emit .tbz. xConvert accepts the .tb2 variant directly.
Why does 7Z compress better than bzip2 on text?
bzip2 uses the Burrows-Wheeler Transform on 100-900 KB blocks — each block is independent, so cross-block redundancy is lost. LZMA2 keeps a sliding dictionary up to 4 GB and finds matches across the entire archive. For source trees or log bundles with many repeated tokens, that wider context window translates directly into a smaller file.
Does the converter unpack and inspect my files?
The server decompresses the bzip2 stream, reads the TAR table of contents to enumerate entries, and re-packs into a 7z container. Filenames and contents are not stored after the conversion completes — files are deleted from the processing server after download. No third-party indexing.
Should I keep the TAR layer inside, or strip it?
If your archive contains a Linux/Unix filesystem snapshot (a source tree, a backup of /etc, a chroot), keep the TAR — POSIX metadata is irreplaceable. For mixed Windows/Mac/Linux content where filenames matter more than UNIX permissions, a flat .7z is simpler and smaller. The xConvert default flattens to a clean 7z; if you need TAR-in-7Z, route through TB2 to TAR first.
What's the difference between converting TB2 to 7Z and just re-compressing with tar.xz?
xz (LZMA2 in an xz container) gives you most of the size win without changing the TAR-based packaging. Choose .7z when you also want random-access listing, optional AES-256 encryption, or a single-file Windows-native container. Choose .tar.xz when you need to preserve every POSIX detail and stay in Unix tooling — see TB2 to TAR.GZ or stay on tar-based formats.