Convert WebM to MP4
We turn WebM into MP4 right in your browser — the file never goes to a server.
What you will lose
Nothing important: the target format does everything the source does.
How they differ
| WebM | MP4 | |
|---|---|---|
| Lossless | no | no |
| Lossy | yes | yes |
| Multichannel | yes | yes |
| Tags | yes | yes |
| Released | 2010 | 2001 |
| Author | MPEG |
WebM
Good at
- The browser’s own format: plays with no plugins at all
- Free of patent fees, which is why sites reach for it
- Noticeably lighter than older-style MP4 at the same quality
Awkward about
- Household devices and editing software barely know it
- On Apple hardware it plays only sometimes
- Audio is lossy only: Vorbis or Opus
Use it when
- The video goes on a web page and is watched in a browser
- You want the smallest file with the picture still alive
- A screen recording or a short clip for a page
MP4
Good at
- Plays on everything: TVs, car stereos, phones a decade old
- Carries several audio tracks, subtitles and chapters in one file
- Streams well: playback starts before the file has finished loading
Awkward about
- Anything can be inside — the extension does not tell you if it will play
- The audio is almost always lossy, so it is not a master copy
- Editing without re-encoding is close to impossible in this container
Use it when
- The video is being sent or published and has to open for everyone
- Footage from a phone that people will simply watch
- One audio track is all you need
Common questions
- Does the file get uploaded to a server?
- Yes, this pair needs the server: browsers cannot encode that format. The file and the result are deleted within a couple of hours and never shared.
- Will surround sound survive?
- Yes, MP4 carries more than two channels — 5.1 stays 5.1.
- Can I get the original quality back afterwards?
- No. MP4 is lossy, and the discarded detail cannot be recovered. Keep the original if you may still need it.
- How many files, and how large?
- Up to 3 files at a time, 500 MB each. No sign-up, no watermarks.