Free online AU to APE converter

1. Source format: AU

AU is a simple audio file format originally associated with Sun Microsystems and early Unix systems. It is often used for basic sound clips, legacy software, and older audio archives. AU files may contain uncompressed PCM audio or compressed audio using older codecs, and they are still encountered in technical environments, embedded systems, and historical media collections.

2. Target format: APE

APE usually refers to Monkey’s Audio, a lossless audio format designed to compress audio without losing quality. Compared with uncompressed formats, APE can significantly reduce file size while preserving the original samples exactly. It is commonly used by audio collectors and users who want archival-quality storage with smaller files than WAV or AU.

3. How to perform the conversion

The most practical way to convert AU to APE is with a desktop audio converter that supports both formats. A good choice is fre:ac, which can read AU files and export to Monkey’s Audio on supported systems. If your AU file is unusual or uses an older codec, you may first need to open it in a player or converter that can decode it correctly.

1. Install fre:ac or another audio converter with APE/Monkey’s Audio support.
2. Open the program and add your .au file.
3. Choose Monkey’s Audio or APE as the output format.
4. Adjust quality or compression settings if available.
5. Start the conversion and save the resulting .ape file.

If you prefer a command-line workflow, you can often use FFmpeg as an intermediate step when the AU file is supported by your build, then encode to APE with a dedicated Monkey’s Audio encoder. In practice, however, a GUI converter is usually simpler because APE encoding support is less common than decoding support.

You can also convert the file on 101convert.com for free, without installing any software.

4. Notes on quality, compatibility, or limitations

AU to APE is a lossless-to-lossless or lossless-to-lossy-decoding workflow only if the source AU is uncompressed; if the AU file already uses a compressed codec, the conversion will preserve only the decoded audio, not the original compression method. Because APE is lossless, the audio quality will not degrade during encoding, but the file may still be larger than highly compressed lossy formats such as MP3 or AAC.

Compatibility is the main limitation: APE is not as widely supported as FLAC, so some players and devices may not open it without additional software. If broad playback compatibility matters, consider converting AU to FLAC instead. Also, metadata support can vary between tools, so tags from the AU file may not transfer perfectly unless the converter explicitly preserves them.