Audio Conversion
Convert AU to M4A Online — Free
Fast, free AU to M4A converter. No registration required.
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How to Convert
1
Upload your .au file by dragging it into the upload area or clicking to browse.
2
Choose your output settings. The default settings work great for most files.
3
Click Convert and download your .m4a file when it's ready.
What is AU?
AU is an audio format created by Sun Microsystems. It's one of the oldest digital audio formats, commonly used on Unix and Java platforms.
Format Details
- Full Name
- Sun Microsystems Audio
- Extension
- .au
Key Features
- Unix standard
- Java audio
- Simple format
- Legacy support
What is M4A?
M4A is an audio-only MPEG-4 container, commonly using AAC encoding. It provides better quality than MP3 at similar file sizes.
Format Details
- Full Name
- MPEG-4 Audio
- Extension
- .m4a
Key Features
- Better than MP3
- Apple ecosystem
- AAC encoding
- Metadata support
AU vs M4A
| Feature | AU | M4A |
|---|---|---|
| Full Name | Sun Microsystems Audio | MPEG-4 Audio |
| Extension | .au | .m4a |
| Best For | Unix standard | Better than MP3 |
Frequently Asked Questions
Yes. You can convert up to 5 files per day completely free, with no watermark or registration required.
Most files convert in under 30 seconds. Larger files (over 500MB) may take 1-3 minutes.
No. Our converter uses optimized encoding settings by default to preserve the original quality.
Free users can convert files up to 100MB. Pro users can convert files up to 2GB.
Yes. Our converter works in any modern web browser on any device.