How do I convert M4A to AU?

Drop your M4A 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 M4A to AU here?

Yes. M4A to AU conversion happens entirely inside your browser using WebAssembly, so your file is never uploaded to any server.

Is the M4A 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 M4A to AU reduce quality?

No — AU preserves the content of your M4A file as faithfully as the format allows.

Can I convert multiple M4A 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 M4A?

Yes — use our AU to M4A converter. Note that converting back and forth between formats can't recover detail lost to lossy compression.

AU→M4A M4A→MP3 MP3→AU M4A→WAV MP4→AU M4A→FLAC WAV→AU M4A→AAC MOV→AU M4A→OGG M4A→Opus WebM→AU M4A→WMA M4A→AIFF M4A→AMR M4A→M4B M4A→AC3 M4A→MP2 M4A→WEBA M4A→OGA M4A→MKA M4A→WV M4A→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 MP3→WAV 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 MP3→M4A 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 MP3→FLAC 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 MP3→AAC WAV→M4A AAC→MP3 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

M4AAU

Convert M4A to AU

Free, fast and private. Your M4A files are converted right in your browser — nothing is uploaded.

Runs in your browser
No watermark
Batch & ZIP download

Need a smaller M4A? Compress M4A

How to convert M4A to AU

1
Add your M4A files
Drag and drop M4A 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.

M4A vs AU

From

M4A · MPEG-4 Audio

M4A is an audio-only MP4 file, usually containing AAC (or lossless ALAC). It's Apple Music's and Voice Memos' default format.

Type: Audio
Extension: .m4a
MIME: audio/mp4
Best for: iTunes/Apple Music libraries and voice memos

Lossy compression

All M4A 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 M4A.

Related conversions

M4A to AU: frequently asked questions

Free, private and in your browser

Convert M4A 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 M4A to AU

How to convert M4A to AU

Add your M4A files

Choose AU

Convert

Download your AU