Convert MP3 files to OPUS free in your browser — no signup, no install, and the file is never uploaded to a server.
Add your MP3 file
Drag the MP3 file onto the drop area above, or click it to pick a file from your device. You can add several files at once.
Confirm OPUS as the output
OPUS is already selected as the output format on this page. You can pick the bitrate — higher keeps more of the sound, lower makes a smaller file.
Run the conversion
Press the convert button. Audio decodes and re-encodes in your browser — a normal song finishes in a few seconds.
Download the OPUS file
When it finishes, download the OPUS file. Converting multiple files gives you the option to download them together as a ZIP.
The most widely used lossy audio format, discarding sound humans barely perceive to shrink files roughly tenfold. It is hard to find a device that cannot play it.
A modern codec offering the best efficiency available today for both speech and music. Discord, WhatsApp, and other real-time voice services use it.
Yes. MP3 to OPUS conversion is completely free with no signup, no watermark, and no daily limit on the free plan for ordinary use.
No. The conversion runs entirely inside your browser using WebAssembly, so the MP3 file never leaves your device. That is also why it works without an internet connection once the page has loaded.
OPUS is a newer format. Current browsers and phones handle it, but older desktop software may not — keep the original MP3 if you have to send it to someone on an old machine.
The free plan handles files up to 200MB. Because processing happens on your own device, very large files depend on your computer's memory rather than a server quota.
Audio converter
What each file format is, what it is used for, and which formats it can be converted to.
Open converter Browse the full format reference