AR to XZ Converter
FileFlip converts AR to XZ 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 XZ?#
- 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 XZ 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 XZ file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting AR to XZ lose quality?#
No. Converting AR to XZ 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 XZ actually does to the file#
Converting AR to XZ 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 → XZ |
| 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 an XZ file?#
An XZ file is a single stream compressed with LZMA2 inside a container that adds framing, size fields and a CRC or SHA-256 integrity check, specified by the Tukaani project's xz format starting in 2009.
Use XZ when the smallest practical archive size matters more than how long compression takes, which is why Linux distributions compress their packages and kernel source with it.
Convert XZ to GZ when the archive needs to decompress on something old or constrained enough that gzip's lighter decoder matters.
AR to XZ questions people ask#
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.
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.
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.
Why do Linux distributions use .xz for packages?
xz compresses tighter than gzip or bzip2 on most data while still decompressing quickly, which matters because package managers decompress far more often than they compress. That ratio-versus-decompression-speed balance is why Debian, Fedora and the Linux kernel have shipped source and package archives as .xz for years.