Convert a WebM file to an MP4 video

Open the tool, drop in your .webm file, and it re-encodes the video to H.264 and saves it as an MP4. It all happens in your browser, so there is no upload step and no account to create.

Yes. The converter is free to use, with no sign-up, no trial, and no watermark on the result.

No. The conversion runs on your device with WebCodecs, so the WebM never leaves your browser and nothing is stored on a server.

WebM is made for the web and plays well in browsers, but a lot of players, video editors, and phones still refuse it. MP4 with H.264 video is the format that opens almost everywhere, so you convert for compatibility rather than to shrink the file.

Most desktop browsers play WebM, and so does VLC. Many phones, video editors, and built-in players do not. Converting to MP4 is the simplest way to make the same clip open in all of them.

Usually not. WebM uses VP9, which is already efficient, so the MP4 you get back can be a similar size or even a little larger. The reason to convert is compatibility, not size. To make a clip smaller, use the compress tool instead.

The MP4 keeps the original resolution and frame rate. The video is re-encoded to H.264, so a single frame paused and zoomed in can look a touch softer than the WebM. In motion the clip looks the same.

Yes. The tool runs in your phone browser, so it works on iPhone and Android with no app to install. This is handy because an iPhone often will not open a WebM, but it plays the MP4 with no trouble.

There is no server limit, because nothing is uploaded. Very large files are bounded only by your device memory, but the typical clips people convert are no trouble.