Drop in a Opus file and get a MP3 back in seconds. Free, no account, and nothing is kept on our server.
Convert audio files between MP3, WAV, FLAC, AAC, OGG, Opus, and more. Extract audio from video. Powered by FFmpeg — free, no installation.
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Supported formats: MP3, WAV, FLAC, AAC, OGG, OPUS, WMA, M4A, AIFF, AC3, AIFF, AMR
Also: MP4, MKV, AVI, MOV (extracts the audio track) · Max 512 MB
Voice notes downloaded from messengers are Opus. Most editing and transcription software still will not open them.
Opus was standardised by the IETF in 2012 and is the codec behind WhatsApp voice notes, Discord calls and most of what YouTube streams. Below 64 kbit/s nothing else is close. Its weakness is age: hardware built before roughly 2015 often cannot play it at all.
MP3, formally MPEG-1 Audio Layer III, was standardised in 1993 after years of work at Fraunhofer IIS. It discards sound the ear is unlikely to notice, which is how a three-minute track fits into a few megabytes instead of thirty. Nothing else comes close to its reach: every phone, browser, car stereo and cheap player made in the last two decades reads it. That universality, not sound quality, is why it is still the safe default today.
| Opus | MP3 | |
|---|---|---|
| Released | 2012 | 1993 |
| Developed by | IETF (RFC 6716) | Fraunhofer IIS / MPEG |
| Compression | lossy | lossy |
| Typical bitrate | 24-128 kbit/s | 128-320 kbit/s |
| Three-minute track | 1-3 MB | 3-7 MB |
| Quality ceiling | Best in class at low bitrates | Good, not transparent |
| Best suited to | Voice notes, calls, streaming | Sharing, phones, car stereos |
| Playback support | Modern browsers and apps only | Universal |
Slightly. Both formats are compressed, so decoding and re-encoding costs a little detail. At 192 kbit/s and above the difference is hard to hear on normal equipment, but converting the same file back and forth repeatedly will audibly degrade it.
A normal song finishes in a few seconds. Conversion runs on our server rather than in your browser, so the slow part is usually the upload, not the work itself. Long recordings such as lectures or podcasts take proportionally longer.
Your file is uploaded to our server because the conversion runs there. A cleanup task runs every hour and deletes anything older than an hour, so nothing you upload survives more than about two hours. We do not open your files, we do not keep copies, and no account is needed to use the converter.