FLAC to AU Converter
Processing entirely on your device — large files may take a moment.
FLAC is the audiophile’s lossless codec: bit-perfect audio compressed to roughly half its raw size. Converting AU to WAV preserves the samples in a format every modern tool reads.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How FLAC compares to AU
| FLAC | AU | |
|---|---|---|
| Compression | Lossless (~50–60% of PCM) | µ-law or PCM |
| Quality | Bit-perfect | Mono voice-grade (µ-law) |
| Compatibility | Players, Android, hi-res rigs | Legacy Unix tools |
| Best for | Music collections and archival | Old system sounds and recordings |
How to convert FLAC to AU
- 1
Select your files
Drag & drop your FLAC files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to AU". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted AU file individually, or grab everything at once as a ZIP archive.
About the FLAC format
FLAC (Free Lossless Audio Codec, Xiph, 2001) compresses audio to roughly 50–60% of its PCM size and restores every bit on playback — a ZIP for music that also carries proper tags, hi-res support up to 32-bit/655 kHz on paper (24-bit/192 kHz in practice) and full open-source pedigree. It is the archive format of digital music collections.
Support followed maturity: every serious player, modern Android (system-level), most cars and streaming purists' devices handle FLAC natively. Apple resisted for years but iOS 11+ plays it, with the caveat that iTunes/Apple Music syncing still prefers ALAC. The price of losslessness is size — about five times MP3 at comparable quality.
+ Strengths
- ✓Bit-perfect lossless with real compression
- ✓Hi-res capable (24-bit/192 kHz)
- ✓Open, unpatented, tag-native
! Limitations
- −~5× the size of lossy formats
- −Apple syncing prefers ALAC
- −Overkill for casual listening
About the AU format
AU is Sun Microsystems' audio format from the Unix workstation age: a small header followed by µ-law (or PCM) samples. Java's applet era shipped it everywhere, and old Unix sound tooling still emits it.
Modern players increasingly skip it. Converting AU to WAV preserves the samples bit-for-bit while moving the file into universal territory — the standard rescue path for system sounds and old recordings.
+ Strengths
- ✓Simple, lossless sample storage
- ✓Native to old Unix/Java tooling
! Limitations
- −µ-law flavor sounds dated and mono
- −Dropped by modern players
Why convert FLAC to AU?
Think of it as moving your file to the container that fits the job. ~5× the size of lossy formats AU works differently: Simple, lossless sample storage If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this FLAC to AU converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for FLAC to AU?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Can I convert a whole folder of FLAC files?
You can select many files at once and they are processed in a single batch. Output files land in one ZIP download when there is more than one result.
Will converting FLAC to AU reduce audio quality?
If AU is lossless, the output contains everything the FLAC file contains — no further loss is added. If AU is lossy, one recompression pass is unavoidable; the quality slider controls how much. Loss that already happened in the source file can never be undone by converting.