WebM to MP4 — Convert Online for Free
Convert WebM to MP4 right in your browser: video from the web will open in players and editing software. Nothing is uploaded.
Drag and drop your file here or click to select
About the conversion
WebM is an open format designed for the web: browsers serve video in it, screen recordings save into it and many sites hand out clips this way. Inside sit the VP8 or VP9 codecs, and those are exactly what causes friction outside the browser — ordinary players, TVs and editing suites do not understand them.
So a simple container swap will not do here: the video has to be re-encoded to H.264 and the audio to AAC. That takes longer than moving a track, but the result is a file that opens anywhere and is accepted by any editor.
The file is processed in your browser on your own device and is never uploaded — not to our server, not anywhere else. On the first run the browser downloads the engine once (~32 MB) and takes it from cache afterwards.
Frequently asked questions
Why can't WebM just be repackaged into MP4?
Because a WebM holds VP8 or VP9, and the MP4 container does not accept them. The video must be converted to H.264 — a full re-encode, which takes time.
Will the quality drop noticeably?
There should be no visible difference on an ordinary screen: the settings are chosen to keep re-compression losses minimal. Still, since re-encoding is unavoidable, keep the source if you might need it.
Where do WebM files even come from?
Most often a browser screen recording, a video saved from a website, or the output of a web application. The format is convenient for the internet but not for players and editing.
How long will the conversion take?
Longer than pairs such as MOV to MP4 where a container swap is enough. The time depends on the clip length and your device; progress is shown on the bar.
Is the video sent to a server?
No. The whole re-encode runs in your browser on your own device.