MP4 to WebM.

Convert MP4 to open WebM format locally.

Processed locally — no upload. MP4 to WebM runs entirely in your browser. Large files use more memory and processing time depends on your device. Re-encoded video is exported as WebM here (MP4 requires cross-origin isolation, e.g. a production deploy in Chrome/Firefox).

Drop your video here

or click to browse — MP4, WebM, MOV, MKV, M4V

Files stay on your device · nothing is uploaded

Settings

Load a video to configure mp4 to webm.

→ Related

Convert Video

Re-encode to WebM (MP4 with the FFmpeg build).

WebM to MP4

MP4 muxing requires the FFmpeg build; otherwise WebM.

MOV to MP4

Re-encode MOV to a web-friendly clip.

Video to GIF

Turn a short clip into an animated GIF.

? MP4 to WebM FAQ

No. The file is processed locally with the File and Canvas APIs. There is no server upload.

In this browser, re-encoded video is WebM; MP4 needs cross-origin isolation (a production deploy in Chrome/Firefox). Images are PNG and audio is WAV or MP3.

The default engine captures frames in real time for accuracy. The FFmpeg engine is faster where available.