# WebM to MP4

Convert WebM to MP4 so it plays on phones, in editors and on social platforms. Free, no signup, and the file is never uploaded.

Canonical page: https://filetity.com/webm-to-mp4

## Capabilities

- Free: Yes, with no watermark and no page limit.
- Account required: No. There is no account system.
- Processed on device: Yes. The file is read by your browser and never uploaded. There is no server to send it to.
- Formats: WebM in, with VP8, VP9 or AV1 video. MP4 out, H.264 video and AAC audio.
- Limits: This is a real re-encode, so it takes roughly as long as the video is, and longer for high resolutions. The page shows the estimated size before you start.
- Mobile: Yes, on any modern mobile browser. Large files are limited by the memory the phone gives the browser.
- Offline: Yes, once the page has loaded. The tool keeps working with no network connection.

## Questions

### Why does this take longer than converting a MOV?

Because a MOV is usually the same video in a different box and can be copied across, while a WebM holds VP9 or VP8, which nothing outside a browser will play from inside an MP4. So every frame genuinely has to be decoded and encoded again, and that is the time you are waiting for.

### Where do WebM files even come from?

Browser screen and camera recordings, most in-page video recorders, and a lot of download tools. It is an excellent format that plays in every browser and almost nowhere else, which is why anything you want to hand to a phone, an editor or a social platform needs converting.

### Will the MP4 be bigger?

Often slightly, because VP9 is a more efficient codec than H.264, so the same picture needs more bits. The conversion never asks for a higher bitrate than the source spends, which keeps the increase small; if size matters more than compatibility, keep the WebM.

### Is any quality lost?

A little, as with any re-encode: the picture is decoded and compressed again by a different codec. It is not usually visible at normal viewing sizes, and it is unavoidable, because there is no way to carry VP9 into a file an iPhone will open.

### What happens to the audio?

WebM audio is Opus or Vorbis. Opus can be carried into an MP4 as it is, but Vorbis cannot, so it is re-encoded to AAC. Either way the page reports what happened rather than leaving you to discover a silent file later.

## Related tools

- [MP4 to WebM](https://filetity.com/mp4-to-webm): Convert an MP4 to WebM, usually smaller at the same quality.
- [MOV to MP4](https://filetity.com/mov-to-mp4): Convert a QuickTime MOV to MP4, usually without re-encoding it.