How to use it
- Add your files. Drop MP3 files on the page or use Choose files. Folders and ZIPs work too.
- Check that Opus is selected. Opus is already chosen on this page.
- Adjust options if you need to. Quality, size and other settings appear when the format has them.
- Convert and download. Press Convert; with several files, “Download all” gives you one ZIP.
What happens to your file
The audio is decoded and encoded as Opus at the bit rate you choose.
Opus is lossy, so pick a bit rate at least as high as the original’s to avoid audible loss.
About MP3 and Opus
MP3: MP3 is the universal audio format: every phone, car stereo and app plays it.
Opus: Opus is the most efficient modern audio codec, used by WhatsApp voice notes, Discord and WebRTC.
Questions
Is my MP3 file uploaded?
No. The conversion runs inside this browser tab, and the Opus is created on your device. Nothing is sent to a server.
Is there a file size limit?
No fixed limit: files are processed by your device, so very large videos depend on its memory. Computers handle several GB; phones are best with smaller files.
Can I convert several MP3 files at once?
Yes. Drop as many as you like, a folder or a ZIP; “Download all” saves every Opus in one ZIP.