CONVERT
XZ → GZ
Fast, secure XZ to GZ conversion. No registration required.
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Here is the short version — XZ is the LZMA2-based compression format used for tight compression of source tarballs. Hence the need for GZ. Need to turn a XZ into a GZ? 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. Worth knowing: XZ is the LZMA2-based compression format used for tight compression of source tarballs. Meanwhile GZ is the gzip DEFLATE compression format, typically wrapped around TAR for Unix distributions.
XZ Compressed
Source formatXZ provides very high compression ratio using LZMA2, common in Linux packages.
Gzip Compressed
Target formatGzip is a single-file compression format based on the DEFLATE algorithm. It is most commonly paired with TAR to create .tar.gz archives and is the standard compression for web content delivery.
Why convert XZ to GZ
Some GZ formats support features XZ lacks: solid compression across many small files, per-file encryption, streamable headers. Repacking a legacy XZ into a modern GZ is how you opt into those features without changing any of the files inside.
HOW TO CONVERT
XZ → GZ
Start the job
Upload a XZ; 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 GZ codec at a balanced default level.
Save the result
Download the GZ when ready. Nothing about the original contents is logged or retained.
Common Use Cases
Per-file encryption
GZ formats supporting AES encryption let you ship a passworded archive without relying on filesystem-level protection.
Long-term digital preservation
Libraries and archives standardise on GZ for decades-long retention; convert incoming XZ deposits on receipt.
Email-friendly bundles
Corporate mail filters strip XZ attachments but allow GZ; switching container is often the only fix.
Batch vendor submissions
Submission systems (journals, marketplaces, clients) mandate GZ. Non-compliant XZ uploads silently fail.
XZ vs GZ — Strengths and limitations
What each format does best, and where it falls short.
XZ Strengths
- Best-in-class compression ratio among mainstream tools.
- Streaming-capable — can pipe through network.
- Multi-threaded compression available.
- Mature on every Linux distribution.
- Supports integrity checking (CRC32, CRC64, SHA-256).
Limitations
- Slow compression at high levels — 3-5× slower than gzip.
- Memory-hungry: xz -9 can need 700+ MB to compress.
- 2024 supply-chain backdoor damaged trust in the project.
GZ Strengths
- Patent-free, royalty-free — that was the whole point in 1992.
- Universally supported on every OS.
- Fast compression and extremely fast decompression.
- Preserves original timestamps and filenames in the header.
- Streamable — can compress/decompress over pipes.
Limitations
- Compresses one file at a time — needs tar for multi-file archives.
- Older algorithm — Zstandard, xz, and brotli all beat it on ratio.
- Single-threaded in the reference implementation (pigz fixes this).
XZ vs GZ — Technical specifications
Side-by-side comparison of the technical details.
| Specification | XZ | GZ |
|---|---|---|
| MIME type | application/x-xz | application/gzip |
| Extensions | .xz, .txz | .gz, .tgz (with tar) |
| Algorithm | LZMA2 | DEFLATE (LZ77 + Huffman coding) |
| Standard | The .xz File Format specification 1.1.0 | RFC 1952 (gzip), RFC 1951 (DEFLATE) |
| Integrity checks | None, CRC32, CRC64, SHA-256 | — |
| Header | — | 10 bytes: magic, method, flags, mtime, extra, filename, comment, crc, isize |
XZ vs GZ — Typical file sizes
Approximate file sizes for common scenarios.
XZ
- Text/source archive 15-25% of original
- Linux kernel (.tar.xz) ~125 MB
- Firefox source code ~600 MB
GZ
- Plain text file 25-40% of original
- HTML page 20-30% of original
- Source code archive 15-30% of original
- Already-compressed file (JPEG, MP4) 99-100% (no gain)
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) — GZ formats that support it can shrink 20-50% over per-file compression.
- When the XZ contains symlinks, test that they still resolve after conversion; some GZ formats represent them differently on Windows vs Unix.
- Deterministic timestamps (via Advanced → reset mtimes) make the GZ reproducible for CI artefact verification; otherwise two "identical" conversions will produce slightly different bytes.
Frequently Asked Questions
Frequently Asked Questions
Yes. The free tier accepts files up to 100 MB without registration, email capture or watermarks. 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 XZ and GZ use different compression codecs, every entry is decompressed from the XZ and re-compressed for the GZ. 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 XZ and the GZ 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 XZ used an older codec like Deflate. Against modern LZMA2 / Zstd GZ 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 GZ can be re-encrypted with a password of your choice (AES where the target format supports it).
RELATED CONVERSIONS
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See these formats side by side to understand which fits your use case best.
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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.