CONVERT
LZ → LZ4
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Fast, secure LZ to LZ4 conversion. No registration required.
LZ is a compression/archive format used to package or shrink files. Reaching a LZ4 from there is one hop. Need to turn a LZ into a LZ4? The conversion is lossless by definition — archive formats only store file data plus metadata, and every mainstream archive supports the same primitives. File names, folder structure, timestamps and attributes round-trip exactly. A quick refresher — LZ is a compression/archive format used to package or shrink files. By contrast, LZ4 is a compression/archive format used to package or shrink files.
Lzip Compressed
Source formatLzip uses LZMA compression with error detection for reliable archiving.
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 LZ to LZ4
Some LZ4 formats support features LZ lacks: solid compression across many small files, per-file encryption, streamable headers. Repacking a legacy LZ into a modern LZ4 is how you opt into those features without changing any of the files inside.
HOW TO CONVERT
LZ → LZ4
Start the job
Upload a LZ; 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 LZ.
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 LZ 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.
LZ vs LZ4 — Strengths and limitations
What each format does best, and where it falls short.
LZ Strengths
- LZMA compression without xz complexity.
- Per-segment CRC32 integrity.
- Multi-threaded plzip variant.
- GNU FSF endorsement.
Limitations
- Tiny ecosystem vs xz.
- No native Windows GUI tools.
- Rarely default anywhere.
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.
LZ vs LZ4 — Technical specifications
Side-by-side comparison of the technical details.
LZ
- MIME type
- application/x-lzip
- Extension
- .lz
- Algorithm
- LZMA
- Maintainer
- Antonio Diaz Diaz
LZ4
- MIME type
- application/x-lz4
- Algorithm
- LZ77 variant with fast byte-level parsing
- Extensions
- .lz4
- License
- BSD 2-Clause (library), GPL v2 (CLI)
- Typical integrations
- Linux kernel, ZFS, Kafka, RocksDB, Cassandra
| Specification | LZ | LZ4 |
|---|---|---|
| MIME type | application/x-lzip | application/x-lz4 |
| Extension | .lz | — |
| Algorithm | LZMA | LZ77 variant with fast byte-level parsing |
| Maintainer | Antonio Diaz Diaz | — |
| Extensions | — | .lz4 |
| License | — | BSD 2-Clause (library), GPL v2 (CLI) |
| Typical integrations | — | Linux kernel, ZFS, Kafka, RocksDB, Cassandra |
LZ vs LZ4 — Typical file sizes
Approximate file sizes for common scenarios.
LZ
- Source tarball compressed 15-25% of original
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 LZ 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 LZ and LZ4 use different compression codecs, every entry is decompressed from the LZ 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 LZ 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 LZ 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 comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
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Read guideSecure & 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.