Turn M4A audio files into AU. It is converted in your browser, so the file never leaves your device.
Drop M4A files here
or choose from your computer paste with Ctrl V
from Photos or Files
Ready · other file types work too0 bytes uploaded, ever
Drop M4A files onto the box above, or click it to choose them. ToAny reads the file's contents to detect the type, so a wrong extension does not matter.
Press Convert. Open Options first if you want to change the defaults. The work happens in this tab.
Save the AU, or download everything as one ZIP if you converted several files.
The M4A to AU converter is part of this page and runs inside your browser. Your audio files are never sent to ToAny or to anyone else.
Nothing has to travel to a server and back, so the conversion starts the moment you press Convert, even on a slow connection.
No sign-up, no email address and no watermark. Add several files and download them together as a ZIP.
M4A is refused by some car stereos, older players, editors and upload forms. AU is simple and is still read by Unix tools and Java. M4A is at home in music and voice memos on Apple devices; AU is the usual choice for simple uncompressed audio and Unix and Java sound clips. AU cannot bring back detail that M4A compression already removed; it simply stores the result without further loss, in a larger file.
The defaults suit most files. Under Options you can trim the start and end.
This pair uses the compatibility engine, ffmpeg built for the browser, because AU cannot be written by the browser's built-in codecs. It is a one-off download of about 10 MB that the browser keeps, it is slower than the built-in codecs, and it takes files up to 1 GB.
M4A is an MP4 file that contains only audio, usually AAC. iPhone Voice Memos and the iTunes Store use it. It sounds better than MP3 at the same size but is not accepted everywhere MP3 is.
Opens in Apple devices, Android, current browsers; some car stereos and older players do not
M4A converterAU is one of the oldest audio containers: a short header followed by the samples. It comes from Sun workstations and NeXT, was the sound format of early web pages and Java, and often holds 8-bit μ-law telephone audio. Newer files can hold 16-bit PCM or floating point.
Opens in Audacity, VLC, QuickTime and most audio editors
AU converter| M4AM4A audio | AUSun AU audio | |
|---|---|---|
| Stands for | MPEG-4 Audio | Sun/NeXT audio file (AU or SND) |
| Type | Audio | Audio |
| Compression | Lossy (AAC); lossless when it holds ALAC | Usually none |
| Usually contains | AAC, sometimes Apple Lossless | PCM, or μ-law and A-law telephone encoding |
| Introduced | The early 2000s, by the Moving Picture Experts Group (popularised by Apple) | The late 1980s, by Sun Microsystems |
| Opens in | Apple devices, Android, current browsers; some car stereos and older players do not | Audacity, VLC, QuickTime and most audio editors |
| Best for | Music and voice memos on Apple devices | Simple uncompressed audio and Unix and Java sound clips |
| File extension | .m4a | .au, .snd |
No. The M4A to AU conversion runs inside your browser, on your own phone or computer. The file is not sent to ToAny or to anyone else.
No further quality is lost: AU stores the decoded audio exactly. It cannot restore what M4A compression already discarded, and the file will be larger.
Yes. Add as many as you like, convert them together and download each result or all of them as one ZIP.
The steps are the same everywhere because ToAny runs in the web browser: open this page in a current version of Chrome, Edge, Safari or Firefox, add the M4A file, press Convert and save the AU. There is nothing to install.
Yes. M4A to AU runs on the compatibility engine, which takes files up to 1 GB, and a long clip takes a while because it is slower than the browser's built-in codecs. Beyond that the limit is your device's memory, since nothing is uploaded; a computer copes with large files better than a phone.