AU
→
FLAC

Convert AU to FLAC Online

Convert AU to FLAC online. Start with free daily conversions, no install, no watermarks, and visible job status.

AU to FLAC Converter

Upload your AU file to convert it to FLAC format

Loading converter...

How to Convert AU to FLAC

Follow these simple steps

1

Step 1: Upload Your File

Upload your AU file by dragging and dropping or clicking to browse

2

Step 2: Select Output Format

FLAC is automatically selected as the output format

3

Step 3: Start Conversion

Click the Convert button to start the conversion

4

Step 4: Download Result

Download your converted FLAC file when ready

Convert AU to FLAC - Complete Guide

Converting AU to FLAC stays in the audio file family but changes the traits that decide size, quality, transparency, editability, or device support. AU is a audio format. Sun audio. FLAC is a lossless audio format used for high-quality music archives without the large size of raw audio. Below is what actually changes in a AU→FLAC conversion, what is preserved, and when FLAC is the better choice than keeping AU.

What changes when you convert AU to FLAC

  • The audio is re-encoded into the FLAC format. Because re-encoding is not free, start from the highest-quality source you have and keep quality settings high.
  • FLAC is widely supported for streaming, browsers, and uploads, so the result plays on more devices and platforms than AU.

About the AU format

AU is a audio format. Sun audio.

  • Compression: mixed
  • Opens with: VLC, Audacity, FFmpeg

Where AU is strong: simple legacy format from Sun/NeXT systems; stores uncompressed PCM or companded mu-law/A-law audio; easy to read and parse.

Typical AU uses: legacy Unix and Java system sounds, older audio archives.

About the FLAC format

FLAC (Free Lossless Audio Codec) offers CD-quality audio with file compression. It preserves every bit of audio data while reducing file sizes by 50-60% compared to WAV.

  • Full name: Free Lossless Audio Codec
  • Developer: Xiph.Org Foundation
  • Compression: Lossless compression
  • Opens with: VLC, foobar2000, most modern players

Where FLAC is strong: lossless quality at roughly half the size of WAV; supports rich metadata and cover art; ideal for archiving music.

Typical FLAC uses: hi-fi music archives, lossless backups of CDs, audiophile playback.

What FLAC keeps

  • FLAC adds: lossless quality at roughly half the size of WAV.

Things to watch out for

  • One FLAC limitation to keep in mind: larger than MP3.

When to convert AU to FLAC

  • Convert AU to FLAC for hi-fi music archives.
  • Convert AU to FLAC for lossless backups of CDs.
  • Convert AU to FLAC for audiophile playback.
  • Choose FLAC when a website, browser, or upload form rejects your AU file.

AU vs FLAC — format comparison

A quick side-by-side of the structural differences between AU and FLAC, so you can confirm this is the right conversion for your file:

AttributeAUFLAC
TypeAudio fileAudio file
CompressionFlexible (lossy or lossless)Lossless
Web-friendlyNoYes
Typical file sizeMediumMedium
Best forlegacy Unix and Java system soundshi-fi music archives

Privacy & Security

Files are handled for the conversion you request. Uploads and downloads use HTTPS/TLS, and temporary files are cleared after the processing and deletion window.

Add this AU to FLAC converter to your site

Put a working AU to FLAC converter on your own blog or website — free to embed. Both options below include a small link back to FreeFastConverter.

Embeddable widget (iframe)

Paste this where you want a live converter. Visitors can convert AU to FLAC without leaving your page:

Widget Embed Codeiframe

Simple link badge

Prefer a lightweight button instead? Copy this HTML badge:

HTML Badge CodeLink

Need the opposite conversion?

Convert FLAC to AU

Other AU Conversions

More formats you can convert AU to

Convert AU to MP3Convert AU to WAVConvert AU to AACConvert AU to OGGConvert AU to M4AConvert AU to WMAConvert AU to AIFFConvert AU to OPUSConvert AU to AC3Convert AU to AMRConvert AU to CAFConvert AU to MKAConvert AU to WVConvert AU to SPXConvert AU to OGAConvert AU to DTSConvert AU to MP2
View all AU conversions →

Convert to FLAC

Other formats you can convert to FLAC

Convert MP3 to FLACConvert WAV to FLACConvert AAC to FLACConvert OGG to FLACConvert M4A to FLACConvert WMA to FLACConvert AIFF to FLACConvert OPUS to FLACConvert AC3 to FLACConvert AMR to FLACConvert CAF to FLACConvert MKA to FLACConvert WV to FLACConvert SPX to FLACConvert OGA to FLACConvert DTS to FLACConvert MP2 to FLAC
View all FLAC conversions →

Popular Related Conversions

Convert MP3 to FLAC

AU to FLAC FAQ

Converting AU to FLAC preserves the content faithfully; output also depends on the source file and any settings you choose.
Upload your AU file, confirm FLAC as the output format, and click Convert. Job status is shown while the file is processed, then you can download the FLAC result.
Yes. You can start with free daily conversions, with no signup required for your first jobs and no watermarks on the output. Accounts and paid plans are available for higher-volume work.
No. The AU to FLAC conversion runs in your browser on any device — Windows, Mac, Linux, iOS, or Android — with uploads and downloads over HTTPS.
FLAC is a lossless audio format that compresses audio files without any quality loss. It's like ZIP for audio.
FLAC preserves all audio data (lossless), while MP3 removes some data to reduce size (lossy). FLAC is higher quality but larger.
Converting to MP3 will reduce quality as MP3 is lossy. Choose 320 kbps when you need a higher-bitrate MP3 output.
Services like Tidal and Amazon Music HD support FLAC. Spotify uses Ogg Vorbis, so FLAC would be converted.
Processing time depends on file size, format, and queue load. The page shows job status while conversion runs.
Yes. You can add multiple AU files to a batch and process them together within the current file-size and credit limits.

Related tools

Convert AU to FLAC Now

Start with 10 free daily conversions. No signup required for your first file jobs.

Convert Now