MP3 to Opus Converter
Convert MP3 to Opus free — no upload, no signup
To convert MP3 to Opus, drop your MP3 audio files into the box below and click Convert. Fylo converts with ffmpeg running inside your browser, so nothing is uploaded and there's no signup or watermark. Opus keeps voice and music clear at smaller sizes than MP3.
Drop audio files here
or tap to browse · paste with Ctrl+V · add many at once
Your files never leave your device
Advanced
How to convert MP3 to Opus
Add your MP3 files
Drag and drop MP3 files into the box or tap to choose them. The converter engine (about 31 MB) downloads once, the first time you convert.
Pick a bitrate
192 kbps suits music and 128 kbps or less suits speech. Sample rate and mono/stereo are under Advanced.
Convert and download
Click Convert, then download each Opus file or all of them as one ZIP.
Why convert MP3 to Opus?
Discord bots, WebRTC apps and voice-note style apps use Opus because it's efficient at low bitrates.
What happens when you convert MP3 to Opus?
Fylo re-encodes to Opus at 48 kHz using FFmpeg's built-in encoder, 160 kbps by default. Lower the bitrate to 96 kbps for speech to save space.
How does Fylo convert MP3 to Opus?
Fylo decodes the MP3 audio in the MP3 with ffmpeg compiled to WebAssembly and encodes it with FFmpeg's native Opus encoder at 160 kbps and 48 kHz in an Ogg container. Both formats are lossy, so each conversion discards a little detail — start from the highest-bitrate MP3 you have. A 3-minute song is ≈ 4.3 MB at 192 kbps as MP3 and ≈ 2.9 MB at 128 kbps as Opus. Opus always runs at 48 kHz, so the audio is resampled if needed.
What's the difference between MP3 and Opus?
MP3 (MPEG-1 Audio Layer III) was developed largely at Germany's Fraunhofer Institute and standardised in 1993. It removes sounds the ear is unlikely to notice — a technique called perceptual coding — so a 3-minute song takes about 4 MB at 192 kbps instead of about 32 MB as WAV. The last MP3 patents expired in 2017, so it's now free to use.
Opus is an open, royalty-free codec standardised by the IETF as RFC 6716 in 2012. It blends speech technology from Skype's SILK with music coding from Xiph's CELT, so it handles both voice and music well. Files are usually stored in the Ogg container with the .opus extension.
Learn more: MP3 format guide · Opus format guide
| Property | MP3 | Opus |
|---|---|---|
| Compression | Lossy | Lossy |
| Typical bitrate | 128–320 kbps | 24–160 kbps |
| 3-minute song | ≈ 4.3 MB at 192 kbps | ≈ 2.9 MB at 128 kbps |
| Tags and cover art | Yes (ID3) | Yes (Vorbis comments) |
| Compatibility | Universal | Browsers, Android, WhatsApp, Discord; partial on Apple |
| Best for | Music and podcasts on any device | Voice notes, podcasts, streaming at low bitrates |
| Introduced | 1993 | 2012 |
Frequently asked questions
What bitrate should I use for voice?
96 kbps or lower is plenty for speech in Opus.
Can iPhones play Opus?
Recent iOS versions play Opus in some apps, but MP3 is safer for Apple users.
Is my MP3 file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your MP3 file is read directly from your device and never sent anywhere.
Related tools
Updated