Video

WebM to MP4

Convert a WebM video to MP4 (H.264/AAC).

WebM file

Choose a file to convert. It's processed locally — never uploaded. Tip: add several files to convert them all at once.

Output

Result appears here after you select

{ } How to use

  1. Choose the .webm file.
  2. Select Process. The clip is re-encoded to H.264 video and AAC audio.
  3. Download the MP4.

{ } How it works

WebM to MP4 works on the file you upload. Select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.

Input

  • WebM file — upload a file (.webm,video/webm); it is read locally in your browser

Output

A downloadable MP4 file — use the Download button in the Output panel.

{ } Common uses

  • Play a WebM download on a phone, a TV or an editor that only accepts MP4.
  • Get a clip into a video editor that will not import VP8 or VP9.
  • Upload to a service that takes MP4 and nothing else.

{ } Limitations

  • Re-encoding is unavoidable here. WebM carries VP8 or VP9 video with Opus or Vorbis audio, and none of those can be placed in an MP4 that ordinary players will open — so the clip is decoded and encoded to H.264 and AAC, at the cost of a generation of quality and a wait roughly as long as the clip.
  • No quality setting is exposed; the encoder runs at its default. Use Compress Video to choose one.
  • Transparency is lost. VP9 can store an alpha channel and H.264 cannot, so a WebM with a transparent background arrives with that background filled in, usually black.

{ } FAQ

Is my data uploaded to a server?

No. Everything runs locally in your browser — your files never leave your device.

Can I process more than one file at once?

Yes — add several files and they’re all processed and downloaded together as a ZIP.

Is this tool free?

Yes — it’s completely free and needs no sign-up.

If WebM is the open format, why is MP4 the compatible one?

Because H.264 decoding is built into the hardware of essentially every phone, TV and browser shipped in the last decade, while VP9 support is newer and much patchier outside browsers. WebM is the better format on the open web; MP4 is the one that plays everywhere else.