AU to OPUS converter
Convert AU to OPUS in seconds, free and unlimited. No upload, no sign-up, no watermark: your audio never leaves your device.
Last updated
Quick answer: To convert AU to OPUS, add the AU file to the iHateFiles AU to OPUS converter and press Convert. The conversion runs in your browser, so the file is never uploaded, and it is free with no sign-up, watermark or size limit. AU is a format most software has stopped opening. OPUS is not.
Should you convert AU to OPUS?
Do this to make a lossless recording small enough to share or carry around. Keep the AU as the master copy.
AU is lossless and OPUS is not
This is the conversion lossy formats were designed for: from up to 10 MB per minute to 0.25 to 1 MB. At 192 kbps or more almost nobody can hear the difference in music. Keep the AU as your master if you might need to convert again.
Where the OPUS will play
OPUS plays on browsers, Android, WhatsApp and Discord, but not many car stereos or older players.
AU and OPUS side by side
| AU | OPUS | |
|---|---|---|
| Inside the file | PCM or µ-law | Opus |
| Compression | Lossless | Lossy |
| Carries sound | Yes | Yes |
| One minute of stereo | up to 10 MB | 0.25 to 1 MB |
| Plays on | Needs converting first | browsers, Android, WhatsApp and Discord, but not many car stereos or older players |
| Here | Read only | Read and write |
What usually goes wrong
About the AU. Many AU files use 8-bit µ-law companding, which sounds like a telephone. That is how they were recorded, not a conversion fault.
About the OPUS. Opus at 64 kbps sounds better than MP3 at 128, so the bitrate you are used to is roughly double what you need here.
How to convert AU to OPUS
- Add your AU file. It is read from your disk and stays there.
- Check the settings. The output format is already set to OPUS.
- Press convert and the OPUS file is saved back to your device.
Questions
How do I convert AU to OPUS?
Open this page, add your AU file, and press convert. The file is decoded and re-encoded by your own browser and saved back to your device. Nothing is uploaded.
Is this AU to OPUS converter free?
Yes, completely. There is no account, no sign-in, no watermark and no daily limit, because there is no server doing the work. Your own device does it.
Are my files uploaded anywhere?
No. There is no upload endpoint. The conversion runs inside this browser tab, so your file never leaves your device. You can open your browser's network panel and watch: nothing carrying your file is sent.
Is there a file size limit?
No fixed limit. Because the work happens on your machine there is no server quota. The only ceiling is your own device's memory, which for video means very large files may be slow.
Will converting to OPUS lose quality?
OPUS is a lossy format, so some detail is discarded. The quality control on this page decides how much. The default is set high enough that most people cannot see the difference.
Can I convert several AU files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP.