Add your WMA file
Drop one or more .wma files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
WMA to OPUS
Re-encoding .wma audio as .opus changes how the sound is compressed and which players will accept it. Free, private, and validated — the file never leaves your browser.
100% private for supported formats
Runs on your deviceConvert supported files
Drop WMA files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting Windows Media audio to Opus audio
Re-encoding .wma audio as .opus changes how the sound is compressed and which players will accept it. A .wma file contains Windows Media Audio, Microsoft's proprietary compressed format, wrapped in the same ASF container as WMV video. It shipped with every copy of Windows for a decade, so ripped CDs and store purchases from that era survive as .wma libraries.
An .opus file contains audio compressed with the Opus codec, stored in an Ogg container. Opus represents the current state of the art in lossy audio, beating MP3, AAC, and Vorbis in listening tests at nearly every bitrate from whisper-thin speech settings up to transparent music encoding. For this route the practical draw is best-in-class efficiency at essentially every bitrate and royalty-free with an open reference implementation — balanced against older car stereos, AV receivers, and MP3 players have never heard of it, which is worth knowing before you commit a large batch.
Why convert WMA to OPUS?
The practical trigger for this conversion is usually a mismatch: with .wma, proprietary and effectively abandoned. Switching to .opus buys you best-in-class efficiency at essentially every bitrate, which is why it is the better fit for compressing podcast and voice-chat audio to tiny files. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
WMA vs OPUS at a glance
| Aspect | Windows Media audio (.wma) | Opus audio (.opus) |
|---|---|---|
| Format type | Lossy — discards detail it judges invisible to shrink files | Lossy — discards detail it judges invisible to shrink files |
| How it stores data | the standard codec is a lossy transform coder supporting up to 48 kHz stereo | the hybrid SILK/CELT design switches coding modes automatically based on content |
| Strongest at | converting old ripped-CD libraries to MP3 or FLAC | compressing podcast and voice-chat audio to tiny files |
| Weak spot | proprietary and effectively abandoned | older car stereos, AV receivers, and MP3 players have never heard of it |
| Metadata | aSF attributes mirror ID3 basics such as title, artist, album, and artwork, and Windows Media Player wrote extended library fields on top | vorbis comments in the OpusTags header, including cover art via METADATA_BLOCK_PICTURE, plus an output-gain field used for loudness normalization |
Pick OPUS as the output
Select .opus in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if OPUS is selectable, the route is real and validated.
Convert on your device
Press Convert. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid OPUS file. Outputs keep the original filename with the .opus extension.
WMA to OPUS questions, answered
Will converting WMA to OPUS lose quality?
A second lossy step always costs a little, because wma is lossy-oriented and opus is lossy-oriented and each encoder discards detail differently (generation loss). At the default quality the difference is rarely visible; avoid repeated round-trips between .wma and .opus.
Is it private to convert WMA files here?
Yes — the .wma file is processed inside your browser tab and never uploaded. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device. Close the tab and the file is gone from memory.
Where will the OPUS file work?
Chrome, Firefox, and Edge have played Opus for a decade and Android supports it natively, while Safari initially accepted the codec only inside CAF or WebM wrappers before extending support to .opus files. Legacy hardware such as older car head units remains the real gap, and conversion to MP3 or AAC bridges it.
Will the OPUS file be bigger or smaller than my WMA?
It depends on the content: the hybrid SILK/CELT design switches coding modes automatically based on content. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my WMA file?
This converter strips container metadata deliberately (the FFmpeg command runs with metadata mapping disabled) so exported files do not leak recording details. In the source, aSF attributes mirror ID3 basics such as title, artist, album, and artwork, and Windows Media Player wrote extended library fields on top; none of it is transmitted anywhere because the file never leaves your browser.