Z to ZIP Converter
FileFlip converts Z 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 Z file to ZIP?#
- Drop your Z 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 Z to ZIP lose quality?#
No. Converting Z 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 Z files online?#
Yes, because nothing is uploaded. FileFlip converts Z 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 Z to ZIP actually does to the file#
Converting Z 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: Z → 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 Z file?#
A Z file is a single stream compressed with the LZW algorithm by the Unix compress utility, the format gzip was written specifically to replace once a patent on LZW made distributing compress a legal risk.
There's essentially no reason to create a new Z file today; gzip replaced it decades ago with better compression and no patent risk.
Convert an old Z file to GZ or XZ so modern tools that dropped compress support can actually open it.
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.
Z to ZIP questions people ask#
Is a .Z file the same as gzip?
No. A .Z file is compressed with the older Unix compress utility's LZW algorithm, not gzip's DEFLATE, and the two aren't interchangeable; a tool built to read .gz files can't decompress a .Z file.
Why was Unix compress replaced by gzip?
Unix compress used the LZW algorithm, which Sperry, later Unisys, held a patent on, and the resulting licensing risk pushed the Free Software Foundation to write gzip as a patent-free, better-compressing replacement in 1992. Compress fell out of use well before the LZW patent itself expired in 2003.
Can modern tools still open a .Z file?
Many can: gzip itself can decompress .Z files even though it can't create them, and tools like 7-Zip and The Unarchiver read the format too. Native support has thinned out over the decades, so an old .Z file that a tool won't open usually just needs a dedicated uncompress utility or a converter.
Why can I open one file from a ZIP without extracting the whole thing?
A ZIP archive compresses each file inside it separately and lists them in a central directory at the end, so a tool can jump straight to one entry and decompress only that file. Formats like TAR.GZ compress everything as one continuous stream and don't have this shortcut.