How to convert WMV to MP4
Drop your WMV files into the box above, or click Choose files. You can add several at once.
Choose a quality. It only matters if the video has to be re-encoded; compatible videos are copied without any loss.
Click Convert to MP4. Files are processed on your device; a few minutes of media usually takes seconds.
Download the MP4 files one by one, or all at once as a ZIP.
Why convert WMV to MP4?
WMV is Windows Media Video, Microsoft's format from the Windows XP era. Macs, iPhones, Android phones, browsers and most upload forms can't play it.
MP4 with H.264 video and AAC sound plays everywhere, so old recordings, presentations and Movie Maker projects become easy to watch and share again.
Converting in your browser keeps family videos and work recordings on your own device: nothing is uploaded.
WMV vs MP4
WMV files use Microsoft's own Windows Media Video and Windows Media Audio codecs inside an ASF container. Outside Windows, few players support them.
The conversion re-encodes the video to H.264 and the sound to AAC, the most widely supported combination there is, usually at a similar or smaller size.
| Property | WMV | MP4 |
|---|---|---|
| Typical video codec | Windows Media Video (WMV 7–9) | H.264 (AVC), sometimes H.265 or AV1 |
| Typical audio codec | Windows Media Audio (WMA) | AAC |
| File size | Efficient for its time | Efficient |
| Best for | Old Windows recordings and Movie Maker projects | Sharing and uploading video anywhere |
| Support | Windows Media Player and VLC; not browsers, iPhones or Macs | Every phone, browser, TV and editing app |
Is it safe?
Yes. WMV to MP4 runs entirely in your browser. Your files are read and converted by your own device using built-in browser technology, so they are never uploaded to a server and nobody else can see them.
You can check this yourself: open your browser's developer tools, switch to the Network tab and convert a file. No upload requests are made.
AVI and WMV are opened by FFmpeg, the open-source engine behind VLC and most video tools, compiled to run inside your browser. It's downloaded once (about 10 MB) the first time you convert one of these files. Your video is read and converted on your device and never uploaded.
Files stay in this tab's memory only until you remove them or close the page.
Frequently Asked Questions
Why won't WMV play on my Mac or iPhone?
Apple never supported the Windows Media codecs, and neither do browsers or most Android phones. As an MP4, the same video plays everywhere.
Can I convert WMA audio too?
Yes. WMA uses the same container as WMV. To get just the sound as an MP3, drop the file on MP4 to MP3, which accepts WMV and WMA as well.
Why is this slower than MOV or MKV to MP4?
Browsers can't read these older formats, so the video is decoded and re-encoded to H.264 by FFmpeg running on one core of your processor, without the graphics hardware the other video tools use. A typical standard-definition clip converts faster than it plays; a long HD film can take a while, and the progress bar shows how far along it is.
Will the video look as good as before?
Re-encoding changes the picture slightly, but at the default High quality the difference isn't visible. H.264 is more efficient than the old Windows Media codecs, so the file is often smaller.
Is there a size limit?
Each video can be up to 1 GB. Files are read from disk in pieces, so they don't need to fit in memory, but very long videos take longer on slower devices.