WMA to Opus Converter
Convert WMA to Opus free — no upload, no signup
To convert WMA to Opus, drop your WMA 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. Shrink WMA audio with efficient Opus.
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 WMA to Opus
Add your WMA files
Drag and drop WMA 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 WMA to Opus?
Opus gives better quality at small sizes than WMA.
What happens when you convert WMA to Opus?
The audio is re-encoded to Opus at 48 kHz, 160 kbps.
How does Fylo convert WMA to Opus?
Fylo decodes the WMA audio in the WMA 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 WMA you have. A 3-minute song is ≈ 3.6 MB at 160 kbps as WMA 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 WMA and Opus?
WMA (Windows Media Audio) was released by Microsoft in 1999 to compete with MP3 and is stored in the ASF container. Windows Media Player ripped CDs to WMA by default for years, so many older music collections are WMA.
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: WMA format guide · Opus format guide
| Property | WMA | Opus |
|---|---|---|
| Compression | Lossy (also Pro/Lossless variants) | Lossy |
| Typical bitrate | 64–192 kbps | 24–160 kbps |
| 3-minute song | ≈ 3.6 MB at 160 kbps | ≈ 2.9 MB at 128 kbps |
| Tags and cover art | Yes | Yes (Vorbis comments) |
| Compatibility | Windows; poor on Mac, iPhone and browsers | Browsers, Android, WhatsApp, Discord; partial on Apple |
| Best for | Old Windows Media Player libraries | Voice notes, podcasts, streaming at low bitrates |
| Introduced | 1999 | 2012 |
Frequently asked questions
Is Opus widely supported?
In browsers and Android, yes; less so in old Windows and Apple apps.
Good for audiobooks?
Yes, at 64 kbps.
Is my WMA file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your WMA file is read directly from your device and never sent anywhere.
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