Compress WMA files
What works with Windows Media Audio files and how to turn them into modern formats.
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How to compress WMA files
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WMA: Microsoft's answer to MP3
WMA (Windows Media Audio) arrived in 1999 as Microsoft's competitor to MP3 and became the default format of Windows Media Player for ripping CDs during the 2000s. It is stored in ASF (Advanced Systems Format), the same container as WMV video. Under the one name there are actually four different codecs:
- WMA (Standard), the common lossy version, typically 64–192 kbps.
- WMA Pro, a more advanced lossy codec with multichannel and high-resolution support.
- WMA Lossless, which stores CD rips without loss, comparable in size to FLAC.
- WMA Voice, a low-bitrate speech codec.
Many WMA files bought from online stores in the 2000s were protected with Windows Media DRM and only play on authorized computers. Today you meet WMA mostly in old music collections, dictation devices, voicemail exports and archives of Windows PCs.
WMA and the browser
No current browser can decode WMA. Chrome, Edge, Firefox and Safari include decoders for MP3, AAC, Opus, FLAC and WAV, but not for any Windows Media codec, and WebCodecs, the browser interface the tool uses for audio, does not cover them either. The tool recognizes a WMA file and asks you to convert it to WAV or MP3 with a free program such as VLC or Audacity first, instead of producing a broken result.
That makes WMA one of the few formats where a desktop program is the practical answer. Free options include VLC on Windows, macOS and Linux (Media › Convert/Save), and on Windows the Media Player app or the older Windows Media Player can rip and convert. Convert to one of the formats below, then use this site to bring the result down to a specific size if needed.
Which format to convert WMA to
| Your WMA | Convert to | Reason |
|---|---|---|
| Lossy music collection | MP3 or AAC at the same bitrate or slightly higher | Plays on every device; going lower stacks a second loss |
| WMA Lossless CD rips | FLAC or ALAC | Lossless to lossless, no quality is lost |
| Dictation or voicemail | MP3 or Opus, mono, 32–64 kbps | Small and universally playable for transcription services |
| DRM-protected files | Cannot be converted | The protection prevents decoding outside licensed players |
For lossy WMA music, converting at a bitrate lower than the source rarely pays off: quality drops twice, and WMA files from that era are usually 128 kbps or less already.
Why it is worth moving away from WMA
- Phones. iPhones do not play WMA at all, and support on Android depends on the app.
- Web and messaging. Upload forms, transcription services and messengers increasingly reject WMA or show it as an unknown file.
- Long-term access. Microsoft no longer develops the format. MP3, AAC and FLAC are documented, widely implemented and safe for the future.
WMA questions
Why does my WMA file not work here?
Browsers have no WMA decoder, so this tool cannot read WMA files at all. Convert it with a desktop program first; after that, every format on this site works.
Is WMA better quality than MP3?
At low bitrates such as 64 kbps, WMA Standard was often rated better; at 128 kbps and above the difference is small. Compatibility, not quality, is the reason to convert.
How do I know if my WMA has DRM?
In Windows, right-click the file, open Properties and look for the Protected field on the Details tab. Protected files play only on the computers they were licensed for.
Will converting WMA Lossless to FLAC lose quality?
No. Both are lossless, so the decoded audio is identical. Only tags may need to be checked afterwards.
Where to go next
Once converted, compress the result with the MP3 or M4A tools, or use the general audio compressor. More about what runs in the browser and what cannot: how it works.