# Convert AU to FLAC

> Convert AU to FLAC online for free. Runs entirely in your browser, so your files never leave your device. Fast batch conversion, no sign-up, no watermarks.

URL: https://www.converterrr.com/au-to-flac

- Runs in the browser with FFmpeg (WASM): files are not uploaded, and no credits are used.
- Engines: FFmpeg (WASM) (browser), FFmpeg (cloud).
- API: available. `POST /api/v1/jobs` with `"output_format": "flac"` (paid plans).
- More: [Audio converter](https://www.converterrr.com/audio-converter), [AU converter](https://www.converterrr.com/au-converter).

## How to convert AU to FLAC

1. **Add your AU files.** Drag and drop AU files onto the converter, paste them, or click to browse. You can add several at once.
2. **Choose FLAC.** FLAC is already selected. Open Options if you want to change quality, size or metadata.
3. **Convert.** Click Convert. Your files are converted right in your browser in seconds.
4. **Download your FLAC.** Download each FLAC file, or everything at once as a ZIP.

## Good to know

- AU files are typically used for legacy Unix and Java applications, while FLAC is best for archiving CDs and high-fidelity music libraries.
- This conversion runs on FFmpeg (WASM), running locally in your browser — nothing is uploaded and it works even on slow connections.

## AU vs FLAC

|  | AU | FLAC |
| --- | --- | --- |
| Full name | Sun Audio | Free Lossless Audio Codec |
| Type | Audio | Audio |
| Extensions | .au | .flac |
| MIME type | audio/basic | audio/flac |
| Best for | legacy Unix and Java applications | archiving CDs and high-fidelity music libraries |
| Properties | legacy format | lossless, open standard |

**AU:** AU is a simple audio format introduced by Sun Microsystems, common on early Unix systems and Java.

**FLAC:** FLAC compresses audio without losing any quality, typically halving the size of a WAV file.

The other way around: [convert FLAC to AU](https://www.converterrr.com/flac-to-au).

## Related conversions

- [FLAC to AU](https://www.converterrr.com/flac-to-au) (in the browser)
- [AU to MP3](https://www.converterrr.com/au-to-mp3) (in the browser)
- [MP3 to FLAC](https://www.converterrr.com/mp3-to-flac) (in the browser)
- [AU to WAV](https://www.converterrr.com/au-to-wav) (in the browser)
- [MP4 to FLAC](https://www.converterrr.com/mp4-to-flac) (in the browser)
- [AU to M4A](https://www.converterrr.com/au-to-m4a) (in the browser)
- [WAV to FLAC](https://www.converterrr.com/wav-to-flac) (in the browser)
- [MOV to FLAC](https://www.converterrr.com/mov-to-flac) (in the browser)
- [AU to AAC](https://www.converterrr.com/au-to-aac) (in the browser)
- [M4A to FLAC](https://www.converterrr.com/m4a-to-flac) (in the browser)
- [AU to OGG](https://www.converterrr.com/au-to-ogg) (in the browser)
- [WebM to FLAC](https://www.converterrr.com/webm-to-flac) (in the browser)

## Convert AU to other formats

[AU to MP3](https://www.converterrr.com/au-to-mp3), [AU to WAV](https://www.converterrr.com/au-to-wav), [AU to M4A](https://www.converterrr.com/au-to-m4a), [AU to AAC](https://www.converterrr.com/au-to-aac), [AU to OGG](https://www.converterrr.com/au-to-ogg), [AU to Opus](https://www.converterrr.com/au-to-opus), [AU to WMA](https://www.converterrr.com/au-to-wma), [AU to AIFF](https://www.converterrr.com/au-to-aiff), [AU to AMR](https://www.converterrr.com/au-to-amr), [AU to M4B](https://www.converterrr.com/au-to-m4b), [AU to AC3](https://www.converterrr.com/au-to-ac3), [AU to MP2](https://www.converterrr.com/au-to-mp2), [AU to WEBA](https://www.converterrr.com/au-to-weba), [AU to OGA](https://www.converterrr.com/au-to-oga), [AU to MKA](https://www.converterrr.com/au-to-mka), [AU to WV](https://www.converterrr.com/au-to-wv), [AU to TTA](https://www.converterrr.com/au-to-tta)

## Convert other formats to FLAC

[MP3 to FLAC](https://www.converterrr.com/mp3-to-flac), [MP4 to FLAC](https://www.converterrr.com/mp4-to-flac), [WAV to FLAC](https://www.converterrr.com/wav-to-flac), [MOV to FLAC](https://www.converterrr.com/mov-to-flac), [M4A to FLAC](https://www.converterrr.com/m4a-to-flac), [WebM to FLAC](https://www.converterrr.com/webm-to-flac), [MKV to FLAC](https://www.converterrr.com/mkv-to-flac), [AAC to FLAC](https://www.converterrr.com/aac-to-flac), [AVI to FLAC](https://www.converterrr.com/avi-to-flac), [OGG to FLAC](https://www.converterrr.com/ogg-to-flac), [WMV to FLAC](https://www.converterrr.com/wmv-to-flac), [Opus to FLAC](https://www.converterrr.com/opus-to-flac), [WMA to FLAC](https://www.converterrr.com/wma-to-flac), [M4V to FLAC](https://www.converterrr.com/m4v-to-flac), [3GP to FLAC](https://www.converterrr.com/3gp-to-flac), [FLV to FLAC](https://www.converterrr.com/flv-to-flac), [MPEG to FLAC](https://www.converterrr.com/mpeg-to-flac), [AIFF to FLAC](https://www.converterrr.com/aiff-to-flac), [AMR to FLAC](https://www.converterrr.com/amr-to-flac), [TS to FLAC](https://www.converterrr.com/ts-to-flac), [MPG to FLAC](https://www.converterrr.com/mpg-to-flac), [M4B to FLAC](https://www.converterrr.com/m4b-to-flac), [MTS to FLAC](https://www.converterrr.com/mts-to-flac), [VOB to FLAC](https://www.converterrr.com/vob-to-flac)

## AU to FLAC: frequently asked questions

### How do I convert AU to FLAC?

Drop your AU file onto the converter above, make sure FLAC is selected, and click Convert. When it's done, download the FLAC file — it usually takes a few seconds.

### Is it safe to convert AU to FLAC here?

Yes. AU to FLAC conversion happens entirely inside your browser using WebAssembly, so your file is never uploaded to any server.

### Is the AU to FLAC converter free?

Yes — free with no watermark. Signed-out visitors can convert 25 files a day, and a free account raises that to 250.

### Will converting AU to FLAC reduce quality?

No — FLAC preserves the content of your AU file as faithfully as the format allows.

### Can I convert multiple AU files at once?

Yes. Add up to 5 files at a time without an account, 10 with a free account and up to 500 on paid plans, then download them individually or as a single ZIP.

### Can I convert FLAC back to AU?

Yes — use our FLAC to AU converter. Note that converting back and forth between formats can't recover detail lost to lossy compression.