AR to Z Converter
FileFlip converts AR to Z 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 AR file to Z?#
- Drop your AR 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 Z 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 Z file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting AR to Z lose quality?#
No. Converting AR to Z 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 AR files online?#
Yes, because nothing is uploaded. FileFlip converts AR 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 AR to Z actually does to the file#
Converting AR to Z 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: AR → the unpacked files → Z |
| 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 AR file?#
An AR file is a Unix archive that concatenates one or more files behind a short per-file header, the format compilers use for static library .a files and that dpkg uses as the outer wrapper of a .deb package.
Reach for ar when linking a static library, where the .a file it produces is what the linker expects, or when inspecting the outer layer of a .deb package.
Convert an AR archive to tar or zip when the files inside need to be handled by tools that do not know the static-library-oriented ar format.
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.
AR to Z questions people ask#
How is an AR archive different from a TAR archive?
Both concatenate files with a header in front of each, but an AR archive has no directory structure and a much smaller fixed header, since it was built for flat collections like object files rather than whole folder trees. Tar became the general-purpose choice while ar stayed specialized.
What is an AR file used for today?
An AR file's two remaining jobs are holding compiled object files as a static library, with the .a extension, and serving as the outer wrapper of a Debian .deb package. Almost nothing else uses the format anymore.
Why does a .deb package use the ar format?
Debian's package format wraps three items, a version marker and two tarballs, in an ar archive because ar's layout is simple enough to parse without any real library, which keeps tools like dpkg lightweight and lets any ar-aware program open a .deb without understanding Debian packaging at all.
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.