MP4 to WebM Converter
MP4 in.
WebM out.
+
Drop a video here
or choose a file · MP4, MOV, WebM, MKV · processed on your device
To convert MP4 to WebM, drop your MP4 video in, check that WebM is selected and press Convert to WebM. When the codecs allow it the video is copied without re-encoding, so it is fast and lossless; otherwise it's re-encoded on your device.
How to convert MP4 to WebM
- Drop a MP4 file into the box above.
- Make sure WebM is selected (Resolution "Original" keeps full quality).
- Press Convert to WebM — the file downloads when it's ready.
Video formats at a glance
| Format | Usual codecs | Plays on | Typical use |
|---|---|---|---|
| MP4 | H.264 / HEVC + AAC | Everything — phones, PCs, TVs, websites | Sharing and uploading |
| MOV | H.264 / HEVC + AAC | Apple devices, most editors | iPhone recordings, Final Cut |
| WebM | VP9 / AV1 + Opus | Browsers, Android | Web video |
| MKV | Almost any | VLC and media players | Downloads, archives with subtitles |
When to use WebM
WebM with VP9 often produces smaller files than H.264 MP4 at the same quality and is royalty-free, which makes it popular for website background videos and HTML5 players. Keep an MP4 copy for social media and messaging apps.
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Frequently asked questions
- Why convert MP4 to WebM?
- MP4 (H.264/AAC) is the universal video format that plays on every phone, computer, TV and website. WebM is an open web format (VP9/Opus) that many editors, phones and social apps don't accept.
- Are my files uploaded?
- No. Processing happens in your browser using your device's built-in, hardware-accelerated video engine (WebCodecs), so your files never leave your device.
- How long does it take?
- Usually a fraction of the video's length on a modern computer or phone, because your device's video hardware does the work. Large 4K files take longer, and very large files are limited by your device's memory.