LZ to GZ Converter
FileFlip converts LZ to GZ entirely inside your browser, using libarchive compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an LZ file to GZ?#
- Drop your LZ file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to GZ and the conversion starts on its own. FileFlip downloads 1.0 MB of WebAssembly the first time and nothing after that, then runs libarchive on your own machine.
- Save the GZ file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting LZ to GZ lose quality?#
No. Converting LZ to GZ does not touch the files inside the archive. Each member is read out and written back byte for byte, so only the wrapper around them changes and nothing is recompressed.
Is it safe to convert LZ files online?#
Yes, because nothing is uploaded. FileFlip converts LZ files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What LZ to GZ actually does to the file#
Converting LZ to GZ runs on libarchive, downloads 1.0 MB of WebAssembly the first time and nothing after that, copies the archived files through unchanged, keeps file contents.
| Engine | libarchive |
|---|---|
| Conversion path | 2 steps: LZ → the unpacked files → GZ |
| Downloaded to your browser | 1.0 MB, once, then cached by your browser |
| Quality | Lossless, contents copied unchanged |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| File contents | Kept | Carried through into the converted file. |
| File timestamps | Sometimes | Survives for some files and not others. |
| File permissions | Sometimes | Survives for some files and not others. |
Worth knowing before you start:
- the output is a PAX tar archive inside the compressor, not a single compressed stream
- every entry is extracted into memory before anything is written, so a very large archive can exhaust it
What is an LZ file?#
An LZ file is a single stream of data compressed with lzip, an LZMA-based command-line compressor that Antonio Diaz Diaz released in 2008 as a long-term-archival alternative to gzip, bzip2 and xz.
Pick lzip when an archive needs to survive years of storage or transmission and the ability to partially recover a damaged file matters more than having a GUI tool handle it.
Convert an LZ file to gzip or zip when it needs to open on a system whose tools stop at the common formats, which is most of them.
What is a GZ file?#
A GZ file wraps a single DEFLATE-compressed stream in a header that can carry the original filename and modification time, plus a trailing CRC-32 checksum, as defined in RFC 1952.
Use GZ to compress a single file quickly, especially one going over HTTP, where gzip decoding is effectively free.
Convert GZ to XZ when the same data needs to be as small as possible and slower compression is an acceptable cost.
LZ to GZ questions people ask#
What's the difference between LZ and ZIP files?
An LZ file holds a single stream compressed with lzip, not a container of separate files like a ZIP. To pack more than one file as lzip, they need to be combined into a tar archive first and the result compressed as a .tar.lz.
Is lzip the same as LZMA?
Lzip is a specific file format and command-line tool built on the LZMA compression algorithm, the same algorithm 7z and xz also use. The three differ in the container wrapped around that compressed data, and an .lz file will not open with a tool that only understands .xz or .7z.
Why would I use lzip instead of xz?
Lzip trades some tool availability for a format built specifically so a corrupted archive can still be partially recovered, which is why long-term archival projects sometimes prefer it over xz. For everyday compression where recovery from bit rot is not a concern, xz has far broader tool support.
Can a GZ file contain more than one file?
No, gzip compresses exactly one file or stream, so a .gz archive holding several files is actually a tar archive that's been compressed afterward, normally named .tar.gz or .tgz.