GZ to ZIP Converter
FileFlip converts GZ to ZIP 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 a GZ file to ZIP?#
- Drop your GZ 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 ZIP 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 ZIP file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting GZ to ZIP lose quality?#
No. Converting GZ to ZIP 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 GZ files online?#
Yes, because nothing is uploaded. FileFlip converts GZ 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 GZ to ZIP actually does to the file#
Converting GZ to ZIP 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, and drops file timestamps and file permissions.
| Engine | libarchive |
|---|---|
| Conversion path | 2 steps: GZ → the unpacked files → ZIP |
| 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 | On the page's own thread, so a very large file will make the tab wait |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| File contents | Kept | Carried through into the converted file. |
| File timestamps | Dropped | The target format has nowhere to put it. |
| File permissions | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- the built-in ZIP and TAR writer records no timestamps, permissions, or ownership
- every entry is extracted into memory before anything is written, so a very large archive can exhaust it
- this conversion runs on the page's own thread, so a large file will freeze the tab while it works
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.
What is a ZIP file?#
A ZIP file is a container introduced by PKWARE in 1989 that holds any number of files and folders, each one compressed and stored as its own separate entry alongside a central directory listing them.
Use ZIP when the archive has to open on any device without the recipient installing anything, or when individual files need to be pulled out rather than the whole archive at once.
Convert away from ZIP when the same files need to be smaller for storage or transfer, since 7z or xz's solid compression usually beats it at the cost of that per-file random access.
GZ to ZIP questions people ask#
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.
Why does gzip decompress so fast?
gzip uses the DEFLATE algorithm, which was designed for speed rather than maximum compression, so decoding it is cheap enough that web servers gzip-compress HTTP responses on the fly and browsers decompress them with no noticeable delay. Formats built for a tighter ratio, like bzip2 or xz, trade away some of that speed.
What does the .gz header actually store?
A gzip file's header can carry the original filename, the modification time and an operating system flag, and the file ends with a CRC-32 checksum of the uncompressed data plus its original size, all defined in RFC 1952. That checksum is what lets gzip detect a corrupted file on decompression.
Is gzip still used for anything besides old Unix files?
Yes, extensively. gzip is the default compression for HTTP responses across the web, and it's still the most common single-file compressor on Linux and macOS despite bzip2 and xz both compressing tighter.