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 AAC
Re-encoding .wma audio as .aac changes how the sound is compressed and which players will accept it. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
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 AAC audio
Re-encoding .wma audio as .aac 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 .aac file holds raw Advanced Audio Coding data, usually as an ADTS stream. AAC was designed as MP3's successor and delivers audibly better quality at the same bitrate, though the bare .aac extension is rarer than AAC audio traveling inside .m4a or .mp4 files. For this route the practical draw is noticeably more efficient than MP3 at equal bitrates and hardware decoding in essentially every phone and TV — balanced against raw ADTS files handle tags and cover art poorly, which is worth knowing before you commit a large batch.
Why convert WMA to AAC?
The practical trigger for this conversion is usually a mismatch: with .wma, proprietary and effectively abandoned. Switching to .aac buys you noticeably more efficient than MP3 at equal bitrates, which is why it is the better fit for receiving the audio track copied out of MP4 video without re-encoding. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
WMA vs AAC at a glance
| Aspect | Windows Media audio (.wma) | AAC audio (.aac) |
|---|---|---|
| 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 | a pure MDCT transform codec, free of the hybrid filterbank compromise that limited MP3 |
| Strongest at | converting old ripped-CD libraries to MP3 or FLAC | receiving the audio track copied out of MP4 video without re-encoding |
| Weak spot | proprietary and effectively abandoned | raw ADTS files handle tags and cover art poorly |
| Metadata | aSF attributes mirror ID3 basics such as title, artist, album, and artwork, and Windows Media Player wrote extended library fields on top | no standard tag container exists for raw ADTS streams; ID3 tags are sometimes prepended but poorly supported, so wrapping in .m4a is the reliable way to tag AAC |
Pick AAC as the output
Select .aac in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if AAC 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 AAC file. Outputs keep the original filename with the .aac extension.
WMA to AAC questions, answered
Will converting WMA to AAC lose quality?
A second lossy step always costs a little, because wma is lossy-oriented and aac 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 .aac.
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 AAC file work?
AAC decoding is built into every browser, phone, and operating system, whether the audio arrives as a raw .aac stream or inside an .m4a wrapper. The last holdouts are elderly MP3-only car stereos and bargain portable players.
Will the AAC file be bigger or smaller than my WMA?
It depends on the content: a pure MDCT transform codec, free of the hybrid filterbank compromise that limited MP3. 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.
Can I convert AAC back to WMA?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .wma → .aac → .wma is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.