How to convert AU to MP3
- Add your .AU file - drop it in the box above or click to browse.
- Convert it to .MP3 in a few seconds.
- Download your new .MP3 file.
What to expect
- Most AU files are 8-bit mu-law at 8 kHz (telephone quality) - converting to MP3 does not recover missing detail; the output will sound exactly like the source.
- MP3 is a lossy format; if you need to preserve every sample, export to
.wavinstead. - AU stores audio in big-endian byte order, a legacy of its NeXT/Sun origins - modern tools handle this automatically with no manual adjustment needed.
Frequently asked questions
Does converting AU to MP3 lose quality?
MP3 is lossy, so some audio data is removed during encoding. If the source AU is 8-bit mu-law at 8 kHz, the quality was already limited and the MP3 will sound the same. For higher-quality AU files (16-bit PCM, 44.1 kHz), use 192 kbit/s or higher to keep the loss inaudible.
Why does my converted MP3 sound noisy and low-fidelity?
Classic AU files are 8-bit mu-law at 8000 Hz - that is telephone quality with a narrow frequency range and an audible noise floor. The MP3 reflects the source; converting cannot improve it.
Why won't my phone play AU files?
Android and iOS do not include AU decoders in their default media apps. AU is a legacy Unix format; convert to MP3 for mobile playback.
Can I batch-convert multiple AU files?
Yes - Audacity supports batch export via its Macro feature, and
ffmpeg handles batch conversion with a simple shell loop.Programs that convert AU: WavePad · VIP Video Converter · Freemake Video Converter · Pavtube HD Video Converter for Mac · Tiny Audio Converter
