Tools / File Converter / M4R to AU Converter

M4R to AU Converter

Convert M4R files to AU. Free, without uploading.

This tool converts M4R files to AU. M4R is the iPhone ringtone format (AAC audio inside). Ringtones can be up to 40 seconds.

Sun/NeXT audio. AU is lossless, so the audio keeps the quality it has in the M4R file.

Conversion runs on your device; your file is never sent to a server. The components download once on first use, and later conversions start right away.

How to use

1. Choose the M4R file, drag it in, or paste its link.
2. Choose the audio quality; optionally enter a start and end time.
3. Press "Convert" and download the AU file.

Frequently asked questions

Will audio quality drop when converting to AU?

No. AU is lossless.

Is there a file size limit?

No fixed limit; your device’s memory decides. Computers usually handle files up to 1–2 GB.

Is my file uploaded?

No. Your M4R file is converted to AU inside your browser.