How to Convert AU to AAC — Quick & Free
Fast, instant AU to AAC conversion. No signup required. Just drop your .au file and get .aac in seconds.
Batch Settings
About AU to AAC Conversion
Short answer: yes, you can convert AU to AAC online for free, and quality is well preserved with the right settings. Just upload your .au file to CocoConvert, pick AAC as the output, and click Convert. The whole process takes seconds.
Now for the details. AU is a widely used file format. AAC (Advanced Audio Coding) offers better quality than MP3 at the same bitrate — the default codec for Apple devices. Converting between these two formats lets you convert between formats quickly.
Your AU file is decoded and re-encoded as AAC. Converting AU to AAC maintains high quality with CocoConvert's optimised encoder settings.
CocoConvert runs entirely online — no software to install, no account to create. Your files are encrypted during upload (TLS), processed on isolated servers in Germany, and permanently deleted after 24 hours. It works in Chrome, Safari, Firefox, Edge, and all mobile browsers.
Need to convert more than one file? Free users can do 5 per hour. Pro gets 100 per hour with files up to 5 GB each.
How to Convert AU to AAC
- 1
1. Upload AU
Drop your .au file onto the page (or tap "Browse" on mobile). Add multiple files for batch conversion.
- 2
2. Select AAC
Choose .aac from the output dropdown. Settings are pre-configured for best results.
- 3
3. Convert
One click. The server handles all the heavy lifting using FFmpeg and Sharp.
- 4
4. Download
Your .aac file is ready. Download it directly or get all files as a zip archive.
What Happens When You Convert AU to AAC
Your AU file is decoded and re-encoded as AAC.
Your AU file is uploaded and validated
The file is decoded (parsed into its raw data)
The data is re-encoded in AAC format
The converted file is ready for download
Format Comparison
AU
.au file
| Extension | .au |
| MIME Type | audio/basic |
| Category | Audio |
AAC
.aac file
| Extension | .aac |
| MIME Type | audio/aac |
| Category | Audio |
Should You Convert AU to AAC?
When to Convert
- ✓When you need a AAC file
Frequently Asked Questions
Is AU to AAC conversion free?
Yes. CocoConvert offers free AU to AAC conversion with generous daily limits — 25 minutes of processing time and up to 5 files per hour (250 MB each). Pro plans remove these limits.
How fast is AU to AAC conversion?
Most files convert in 2–10 seconds depending on size. Large audio files may take 30 seconds. Batch jobs process in parallel for maximum speed.
What happens to my files after conversion?
Your uploaded AU file and the converted AAC file are both automatically deleted from our servers within 24 hours. They are never shared, sold, or analysed.
Does converting AU to AAC lose quality?
Converting AU to AAC maintains high quality with CocoConvert's optimised encoder settings.
Can I convert AAC back to AU?
Yes, CocoConvert supports AAC to AU conversion as well. However, if the original conversion involved lossy compression, converting back won't recover the lost data.
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