AU
→
AAC

Convert AU to AAC Online

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

AU to AAC Converter

Upload your AU file to convert it to AAC format

Loading converter...

How to Convert AU to AAC

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

AAC 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 AAC file when ready

Convert AU to AAC - Complete Guide

Converting AU to AAC 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. AAC is a compressed audio format used for streaming, mobile playback, and efficient high-quality sound. Below is what actually changes in a AU→AAC conversion, what is preserved, and when AAC is the better choice than keeping AU.

What changes when you convert AU to AAC

  • The audio is re-encoded into the AAC format. Because re-encoding is not free, start from the highest-quality source you have and keep quality settings high.
  • AAC is widely supported for streaming, browsers, and uploads, so the result plays on more devices and platforms than AU.
  • Expect a smaller output file: AAC is typically more space-efficient than AU for the same content.

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 AAC format

AAC (Advanced Audio Coding) is a high-quality audio format that offers better sound quality than MP3 at similar file sizes. It is the default format for iTunes and Apple devices.

  • Full name: Advanced Audio Coding
  • Developer: ISO/IEC
  • Compression: Lossy compression
  • Opens with: Apple devices, most players, browsers

Where AAC is strong: better quality than MP3 at the same bitrate; the standard for Apple and streaming; efficient and widely supported.

Typical AAC uses: streaming audio, Apple Music and iTunes, mobile playback.

What AAC keeps

  • AAC adds: better quality than MP3 at the same bitrate.

Things to watch out for

  • One AAC limitation to keep in mind: lossy compression.

When to convert AU to AAC

  • Convert AU to AAC for streaming audio.
  • Convert AU to AAC for Apple Music and iTunes.
  • Convert AU to AAC for mobile playback.
  • Choose AAC when a website, browser, or upload form rejects your AU file.

AU vs AAC — format comparison

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

AttributeAUAAC
TypeAudio fileAudio file
CompressionFlexible (lossy or lossless)Lossy
Web-friendlyNoYes
Typical file sizeMediumSmall
Best forlegacy Unix and Java system soundsstreaming audio

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 AAC converter to your site

Put a working AU to AAC 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 AAC 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 AAC to AU

Other AU Conversions

More formats you can convert AU to

Convert AU to MP3Convert AU to WAVConvert AU to OGGConvert AU to FLACConvert 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 AAC

Other formats you can convert to AAC

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

Popular Related Conversions

Convert MP3 to AAC

AU to AAC FAQ

Converting AU to AAC preserves the content faithfully; output also depends on the source file and any settings you choose.
Upload your AU file, confirm AAC as the output format, and click Convert. Job status is shown while the file is processed, then you can download the AAC 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 AAC conversion runs in your browser on any device — Windows, Mac, Linux, iOS, or Android — with uploads and downloads over HTTPS.
AAC is an audio format designed to be the successor to MP3. It offers better quality at lower bitrates.
Yes, AAC typically sounds better than MP3 at the same bitrate, especially at lower bitrates (128 kbps).
Most modern devices support AAC, including all Apple devices, Android phones, and newer media players.
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 AAC Now

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

Convert Now