ISO to XZ Converter
FileFlip converts ISO 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 ISO file to XZ?#
- Drop your ISO 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 ISO to XZ lose quality?#
No. Converting ISO 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 ISO files online?#
Yes, because nothing is uploaded. FileFlip converts ISO 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 ISO to XZ actually does to the file#
Converting ISO 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: ISO → 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 ISO file?#
An ISO file is a byte-for-byte image of an optical disc's contents, laid out as an ISO 9660 filesystem that a computer can mount or burn as if it were the physical disc.
Use an ISO when a set of files needs to behave like a disc, most commonly to distribute or boot an operating system installer.
Convert an ISO to a plain archive like ZIP when only the files inside are needed and nothing about them has to boot or be mounted as a disc.
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.
ISO to XZ questions people ask#
How do I open an ISO file?
Windows and macOS both mount an ISO as a virtual disc when you double-click it, after which its files show up like any other drive. On Linux, mounting it with the loop option or opening it in an archive manager works the same way.
Do I need to burn an ISO to a disc to use it?
No. Most ISOs today are Windows or Linux installers meant to be written to a USB drive or booted directly in a virtual machine, and optical drives are rare enough that burning one to a physical disc is now the unusual case.
What's the difference between an ISO and a ZIP file?
An ISO reproduces an entire disc's filesystem, including its boot sector and volume structure, which is why an operating system can boot from one. A ZIP is just a bundle of compressed files with no disc structure or boot capability at all.
Why are ISO filenames sometimes truncated or in all caps?
The base ISO 9660 standard only allows 8.3-style uppercase filenames, a limit inherited from CD-ROM's earliest days. Practically every modern ISO adds the Joliet or Rock Ridge extensions to carry long, mixed-case names alongside the restricted ones, so most tools never show the truncated version.