Convert audio data files (AU) online for free
The converter easily converts your AU audio files to various formats - free and online. No Audacity or or other Audio software needed.
The converter also works in reverse, so you can convert other "Audio Data Block" formats to AU without using software like Audacity or a similar tool.
The .AU file extension primarily represents two distinct formats: an Audacity audio data block or a legacy Sun/NeXT audio file. In Audacity, .AU files are small, unindexed audio chunks stored inside a project's _data folder. These files do not contain full songs; they are roughly 1MB fragments of a larger recording optimized for fast editing. Conversely, the legacy Sun/NeXT .AU format (introduced by Sun Microsystems) is an outdated Unix audio standard. A rare third use case involves the VidMate Android app, which often downloads MP4 video files and renames them to .AU to obscure them.
Working with .AU files presents major challenges. Audacity .AU chunks are practically useless on their own. Opening a single chunk plays only a few seconds of audio, and users frequently make the mistake of trying to convert them directly, which fails without the parent AUP project file. Legacy Sun .AU files are poorly supported by modern web browsers and mobile devices, making playback frustrating without specialized software like SoX or VLC media player.
To solve compatibility limits, you must convert legacy .AU files to standard formats. For universal web and mobile playback, convert to MP3 or AAC. For lossless archiving, convert to WAV or FLAC. If your .AU file is a disguised VidMate download, renaming the extension to MP4 usually restores video playback. Drop your file here to view and convert it securely right in your browser.
Use Convert.Guru to open and convert your AU file.
Users also converted VLC, SND, MP3, AUP3, FSB, MIDI, WAV, DTS, FLA, AVS, NZ, US and KM files.
If you want to convert AU file to NZ, US, KM or M4A, you can use Audacity or similar software from the "Raw Audio Data Storage" category. In the File menu, look for Save As… or Export….
To convert MIDI, MID or RA files to AU, try Audacity or another comparable tool in the "Raw Audio Data Storage" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our AU converter.