CONVERT
BZ2 → LZ4
Tap to choose your fileDRAG. DROP. DONE.
Upload any file and our engines will handle format detection automatically.
Max 25 MB · Free plan · No signup required
Convert to:
Detecting available formats...
Optimize for
Leave empty to use original name. Extension added automatically.
Uploading...
Processing your file...
Fast, secure BZ2 to LZ4 conversion. No registration required.
BZ2 is the bzip2 Burrows-Wheeler compression format, slower but tighter than gzip. That is why users land on this page looking for a LZ4 copy. Going from BZ2 to LZ4 converts the wrapper around a collection of files. If your workflow speaks LZ4 and the backup you were sent is a BZ2, this tool rewraps the bundle for you without asking you to extract and re-compress by hand — and without leaving a scratch folder behind. Context: BZ2 is the bzip2 Burrows-Wheeler compression format, slower but tighter than gzip. LZ4 is a compression/archive format used to package or shrink files.
Bzip2 Compressed
Source formatBzip2 provides higher compression ratios than gzip at the cost of slower speed. It is commonly used for .tar.bz2 archives in Linux distributions where smaller download sizes are preferred.
LZ4 Compressed
Target formatLZ4 is an extremely fast lossless compression algorithm focused on speed over compression ratio. It can compress at over 500 MB/s per core and decompress at multiple GB/s, making it the standard choice for real-time and in-memory compression.
Why convert BZ2 to LZ4
Some LZ4 formats support features BZ2 lacks: solid compression across many small files, per-file encryption, streamable headers. Repacking a legacy BZ2 into a modern LZ4 is how you opt into those features without changing any of the files inside.
HOW TO CONVERT
BZ2 → LZ4
Start the job
Upload a BZ2; we read its header to learn how many entries it carries and the compression method used.
Transcode container
Every entry is decompressed, then recompressed with the LZ4 codec at a balanced default level.
Save the result
Download the LZ4 when ready. Nothing about the original contents is logged or retained.
Common Use Cases
Share across platforms
Send LZ4 files to anyone without worrying about whether they have the right software for BZ2.
Embed in documents
Drop LZ4 output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
LZ4 often produces smaller files than BZ2 for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
BZ2 vs LZ4 — Strengths and limitations
What each format does best, and where it falls short.
BZ2 Strengths
- 10-15% smaller than gzip for the same content.
- Block-based — partial recovery possible from corrupted archives.
- Patent-free, open-source reference implementation.
- Stable for 30+ years with no breaking changes.
Limitations
- Much slower than gzip — 3-5× the compression time.
- Still slower than xz and zstandard at modern levels.
- Single-threaded in reference; pbzip2 fixes this.
LZ4 Strengths
- Decompression speed — approaches memcpy throughput.
- Very fast compression — can keep up with SSD write speeds.
- Stable format — reference implementation unchanged for years.
- Widely deployed in databases, filesystems, and kernels.
- BSD-licensed library.
Limitations
- Compression ratio lags gzip by 20-30%.
- Not designed for long-term archival where ratio matters.
- Older than zstd, which beats LZ4 at comparable speed at slightly better ratio.
BZ2 vs LZ4 — Technical specifications
Side-by-side comparison of the technical details.
BZ2
- MIME type
- application/x-bzip2
- Extensions
- .bz2, .tbz2, .tb2
- Algorithm
- Burrows-Wheeler Transform + Huffman coding
- Block size
- 100-900 KB (configurable)
- Max block size
- 900 KB
LZ4
- MIME type
- application/x-lz4
- Extensions
- .lz4
- Algorithm
- LZ77 variant with fast byte-level parsing
- License
- BSD 2-Clause (library), GPL v2 (CLI)
- Typical integrations
- Linux kernel, ZFS, Kafka, RocksDB, Cassandra
| Specification | BZ2 | LZ4 |
|---|---|---|
| MIME type | application/x-bzip2 | application/x-lz4 |
| Extensions | .bz2, .tbz2, .tb2 | .lz4 |
| Algorithm | Burrows-Wheeler Transform + Huffman coding | LZ77 variant with fast byte-level parsing |
| Block size | 100-900 KB (configurable) | — |
| Max block size | 900 KB | — |
| License | — | BSD 2-Clause (library), GPL v2 (CLI) |
| Typical integrations | — | Linux kernel, ZFS, Kafka, RocksDB, Cassandra |
BZ2 vs LZ4 — Typical file sizes
Approximate file sizes for common scenarios.
BZ2
- Text file 20-30% of original
- Source code archive 15-25% of original
- Linux kernel source (.tar.bz2) ~150 MB
LZ4
- Text file 40-60% of original
- Already-compressed data (JPEG, MP4) 99%+ (no gain)
- Database page (typical) 55-70% of original
Quality & Compatibility
File attributes that both formats understand (modification time, Unix permissions, symlinks) round-trip cleanly. Obscure metadata that one side lacks (e.g., advanced ACLs in one direction) is dropped silently rather than causing the conversion to fail.
Tips for Best Results
- Archives with thousands of tiny files benefit hugely from "solid" compression (one of the Advanced options) — LZ4 formats that support it can shrink 20-50% over per-file compression.
- When the BZ2 contains symlinks, test that they still resolve after conversion; some LZ4 formats represent them differently on Windows vs Unix.
- Deterministic timestamps (via Advanced → reset mtimes) make the LZ4 reproducible for CI artefact verification; otherwise two "identical" conversions will produce slightly different bytes.
Frequently Asked Questions
Yes. The free tier accepts files up to 25 MB without registration, email capture or watermarks; paid plans go up to 2 GB. Paid plans raise the size cap, enable batch conversions and provide a REST API for automation, but nothing on the free tier is quality-limited — the output is exactly the same as on any paid plan.
Yes — because BZ2 and LZ4 use different compression codecs, every entry is decompressed from the BZ2 and re-compressed for the LZ4. The uncompressed data is identical on both sides, and the re-compression happens entirely inside our processing container.
Uploads run over HTTPS, files are processed in isolated containers, and both the source BZ2 and the LZ4 output are auto-deleted within two hours. No account is required, file contents are never logged, and KaijuConverter does not use uploads for AI training. The paid plan adds a signable data-processing agreement for regulated workflows.
Usually yes, modestly, when the original BZ2 used an older codec like Deflate. Against modern LZMA2 / Zstd LZ4 containers expect 10-30% savings on mixed content and almost no change on pre-compressed payloads. Advanced → compression level lets you trade speed for ratio.
Most files finish in well under a minute. Small images and documents are typically ready in a few seconds; large video or audio files scale roughly with duration. Upload speed from your network is usually the dominant factor, not server time.
Yes. Provide the password during upload; we use it only to decrypt inside the processing container and never log or persist it. The resulting LZ4 can be re-encrypted with a password of your choice (AES where the target format supports it).
RELATED CONVERSIONS
Other popular pairs involving BZ2 or LZ4
More from BZ2
More ways to reach LZ4
Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
Secure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.