Convert your audio files to the modern, versatile, and highly efficient Opus audio format. Opus excels at both speech and music, providing excellent quality at very low bitrates. Use our free online tool to convert from MP3, WAV, FLAC, AAC, video, and more to Opus. The service is secure (files deleted automatically within about an hour), free, and requires no registration. Our converter writes Opus at 128 kbps, 48 kHz stereo, in an Ogg container.
Creating Opus audio files is easy:
Opus from the 'Convert to:' dropdown list.Opus is a totally open, royalty-free, highly versatile lossy audio codec. Opus is unparalleled for interactive speech and music transmission over the Internet, but is also intended for storage and streaming applications. It is standardized by the Internet Engineering Task Force (IETF) as RFC 6716.
Opus incorporates technology from Skype's SILK codec (speech-optimized) and Xiph.Org's CELT codec (music-optimized). It can seamlessly adjust bitrate, audio bandwidth, and coding modes, making it incredibly flexible. It achieves high quality across a wide range of bitrates, outperforming most other lossy codecs (like MP3, AAC, Vorbis) especially at lower bitrates (e.g., 64 kbps and below). Opus files typically use the .opus extension.
Opus support is increasingly common in modern software:
For desktop use, VLC or Foobar2000 are excellent choices. On the web and Android, support is often built-in.
| Full name | Opus Interactive Audio Codec |
|---|---|
| Compression | Lossy |
| Developed by | IETF (Xiph.Org, Skype, Mozilla and others) |
| Introduced | 2012 |
| File extension | .opus |
| Typically used for | Voice chat, VoIP, voice notes, streaming |
| Plays on | Chrome, Firefox, Edge, Android, VLC; newer and partial on Apple devices |
| Our output | Opus in Ogg, 128 kbps, 48 kHz stereo |
We encode Opus at 128 kbps in stereo, stored in an Ogg container with the .opus extension. The output is always 48 kHz. That bitrate is generous for Opus: music sounds very good and speech is clearly more than it needs. There are no settings to change.
Opus works internally at 48 kHz, so our converter always outputs 48 kHz and a 44.1 kHz source is resampled. This is normal for the format and doesn't make the audio worse in any audible way. Players decode it at 48 kHz, and virtually all devices handle that rate.
Yes. Opus was designed for both speech and music, and it keeps voices clear even at low bitrates, which is why many voice chat and calling apps use it. At our 128 kbps setting a spoken-word file takes about 0.96 MB per minute, a third less than a 192 kbps MP3.
Support on Apple devices has been limited, especially on older iOS versions, and not every iPhone app opens .opus files even now. A player like VLC handles them reliably. Android, Chrome, Firefox and Edge play Opus natively. If your listeners mostly use Apple devices, M4A or MP3 is the safer choice.
The Opus file is about a third smaller, roughly 0.96 MB versus 1.44 MB per minute. Opus is a newer, more efficient codec, so at 128 kbps it is generally regarded as sounding very close to the original for most listeners. MP3 wins on compatibility with older hardware and car stereos.
No. Our Opus output is always stereo. A 5.1 surround track is downmixed to two channels, and a mono recording is written as stereo with the same sound in both channels. If you need to keep 5.1, choose AAC, M4A or AC3, which keep up to 5.1 channels.
Need detailed information or want to set a different default format? Visit our specific converter pages: