How do I convert MP3 to AU?

Drop your MP3 file onto the converter above, make sure AU is selected, and click Convert. When it's done, download the AU file — it usually takes a few seconds.

Is it safe to convert MP3 to AU here?

Yes. MP3 to AU conversion happens entirely inside your browser using WebAssembly, so your file is never uploaded to any server.

Is the MP3 to AU converter free?

Yes — free with no watermark. Signed-out visitors can convert 25 files a day, and a free account raises that to 250.

Will converting MP3 to AU reduce quality?

No — AU preserves the content of your MP3 file as faithfully as the format allows.

Can I convert multiple MP3 files at once?

Yes. Add up to 5 files at a time without an account, 10 with a free account and up to 500 on paid plans, then download them individually or as a single ZIP.

Can I convert AU back to MP3?

Yes — use our AU to MP3 converter. Note that converting back and forth between formats can't recover detail lost to lossy compression.

AU→MP3 MP3→WAV MP3→M4A MP4→AU MP3→FLAC WAV→AU MP3→AAC MOV→AU MP3→OGG M4A→AU MP3→Opus WebM→AU MP3→WMA MP3→AIFF MP3→AMR MP3→M4B MP3→AC3 MP3→MP2 MP3→WEBA MP3→OGA MP3→MKA MP3→WV MP3→TTA FLAC→AU MKV→AU AAC→AU AVI→AU OGG→AU WMV→AU Opus→AU WMA→AU FLV→AU M4V→AU MPEG→AU 3GP→AU AIFF→AU AMR→AU MPG→AU TS→AU M4B→AU MTS→AU VOB→AU PNG→JPG JPG→PNG PNG→WebP JPG→WebP WebP→PNG WebP→JPG HEIC→PNG HEIC→JPG MP4→MP3 PNG→JPEG JPG→JPEG JPEG→PNG JPEG→JPG PNG→PDF JPG→PDF PDF→PNG PDF→JPG HEIC→WebP MP4→WebP PDF→DOCX DOCX→PDF JPEG→WebP WebP→JPEG PNG→GIF JPG→GIF GIF→PNG GIF→JPG MP4→MOV MOV→MP4 WebP→PDF HEIC→JPEG WebP→GIF GIF→WebP HEIC→PDF WAV→MP3 JPEG→PDF PDF→JPEG SVG→PNG SVG→JPG HEIC→GIF MOV→MP3 MP4→GIF GIF→MP4 JPEG→GIF GIF→JPEG PNG→AVIF JPG→AVIF AVIF→PNG AVIF→JPG M4A→MP3 GIF→PDF SVG→PDF PNG→SVG JPG→SVG PDF→SVG SVG→WebP MOV→WebP MP4→WAV MP4→WebM WebM→MP4 WebP→AVIF AVIF→WebP WebP→SVG SVG→JPEG MP4→MKV MKV→MP4 HEIC→AVIF MP4→M4A JPEG→AVIF AVIF→JPEG JPEG→SVG MOV→GIF GIF→MOV WebM→MP3 AVIF→PDF FLAC→MP3 MP4→AVI AVI→MP4 MKV→MP3 GIF→AVIF AVIF→GIF SVG→GIF GIF→SVG WebM→WebP MOV→WAV XLSX→PDF CSV→PDF EPUB→PDF PDF→EPUB MOV→WebM WebM→MOV MKV→WebP PNG→ICO JPG→ICO ICO→PNG ICO→JPG WAV→M4A AAC→MP3 M4A→WAV MP4→FLAC AVI→MP3 MOV→MKV MKV→MOV MOV→M4A DOCX→EPUB EPUB→DOCX CSV→DOCX PDF→TXT DOC→PDF TXT→PDF WebP→ICO ICO→WebP PPTX→PDF AVI→WebP WebM→GIF GIF→WebM SVG→AVIF MOV→AVI

MP3AU

Convert MP3 to AU

Free, fast and private. Your MP3 files are converted right in your browser — nothing is uploaded.

Runs in your browser
No watermark
Batch & ZIP download

Need a smaller MP3? Compress MP3

How to convert MP3 to AU

1
Add your MP3 files
Drag and drop MP3 files onto the converter, paste them, or click to browse. You can add several at once.
2
Choose AU
AU is already selected. Open Options if you want to change quality, size or metadata.
3
Convert
Click Convert. Your files are converted right in your browser in seconds.
4
Download your AU
Download each AU file, or everything at once as a ZIP.

MP3 vs AU

From

MP3 · MPEG Audio Layer III

MP3 is the most compatible audio format in the world. Its lossy compression keeps music small enough to share while sounding close to CD quality.

Type: Audio
Extension: .mp3
MIME: audio/mpeg
Best for: music libraries, podcasts and audio for any device

Lossy compression

All MP3 conversions →

AU · Sun Audio

AU is a simple audio format introduced by Sun Microsystems, common on early Unix systems and Java.

Type: Audio
Extension: .au
MIME: audio/basic
Best for: legacy Unix and Java applications

Legacy format

All AU conversions →

Need it the other way around? Convert AU to MP3.

Related conversions

MP3 to AU: frequently asked questions

Free, private and in your browser

Convert MP3 to AU in seconds.

No sign-up, no watermarks, no waiting in line. Drop a file and get it back in the format you need.

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Most conversions never leave your device
Cloud files deleted automatically
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Convert MP3 to AU

How to convert MP3 to AU

Add your MP3 files

Choose AU

Convert

Download your AU