Audio Conversion
Convert AU to M4A Online — Free
Fast, free AU to M4A converter. No registration required.
or import from
2M+ Files Converted
Trusted by thousands of users
Secure Transfer
HTTPS encrypted uploads
Privacy First
Files auto-deleted after processing
No Registration
Start converting instantly
Works Everywhere
Any browser, any device
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
Converting between lossless formats preserves perfect quality. When converting to lossy formats, our optimized encoding minimizes any audible difference. You can adjust bitrate to control quality vs. file size.
We preserve ID3 tags, album art, and metadata when both AU and M4A support them. Some metadata may not transfer between incompatible formats.
Pro users can batch convert multiple audio files simultaneously. Free users convert one file at a time with up to 5 free conversions per day.
We support all standard sample rates from 8kHz (voice) up to 192kHz (studio quality). The default preserves your source file's sample rate.
Yes. Our audio converter handles music, podcasts, voice memos, and audiobook files. For podcasts, we recommend MP3 at 128-192kbps for the best balance of quality and file size.