Convert MP3 to AU Online

Convert MP3 to lossless AU for editing, archiving, or mastering. Free.

MP3
MP3
AU
AU
Secure & private
Files deleted in 24h
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Drop your MP3 file here

or click to select

Secure & private
Files deleted in 24h
No signup needed
Select a file to start converting
0 / 10 free conversions used today

Upload MP3

Drag & drop or click to select your MP3 file.

Choose Options

Adjust bitrate, sample rate, or other output settings if needed.

Download AU

Click Convert and your AU file downloads instantly.

Converting MP3 to AU is a common requirement wherever different players, apps, and devices need to exchange audio. Whether you are preparing tracks for a music player, a podcast host, a video project, or meeting an upload requirement, having the file in the right audio format is the starting point for every workflow.

MP3 files are tied to specific software, codecs, and hardware. When that audio needs to move into a context that requires AU - A different player, a DAW, a streaming platform, or a phone that only accepts certain formats - A fast, reliable converter removes the barrier without installing software or knowing anything about bitrates and codecs.

mp3.now processes your file securely in the cloud and returns a clean AU output at the bitrate and quality you choose. Files are processed privately and automatically deleted after 24 hours - Nothing is stored beyond what is needed to complete your conversion.

MP3

MP3 – MPEG-1 Audio Layer III

MP3 is the world's most compatible audio format - Playable on virtually every phone, car stereo, and media player. It uses lossy compression to keep file sizes small at a chosen bitrate.
MP3 Converter
AU

AU – Sun/NeXT Audio

AU is the target audio format for this conversion - Supported by the players and workflows that require it specifically.
AU Converter

Upload your MP3 on mp3.now, select AU as the output, and click Convert. Your AU file downloads in seconds. Read more: What Audio Formats Does mp3.now Support?

Yes, completely free with no signup required. Guests can convert up to 10 files per day. Read more: Is mp3.now Free to Use? No Signup Required

Converting from a compressed MP3 cannot add back detail that was lost, but it does give you a AU file that works in your target app or device without re-compressing further. Read more: Lossy vs Lossless Audio Explained

Yes. mp3.now runs in any mobile browser and saves the converted file straight to your phone. Read more: Does mp3.now Work on Mobile?

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