WEBM -> MP4 · Local tool
WebM to MP4
Convert a WebM to MP4, so phones and editors will play it.
Last updated
How do I convert a WebM to MP4?
Drop the WebM onto filetity's converter and it is re-encoded to H.264 inside the browser tab, with nothing uploaded. This one is a genuine re-encode rather than a container rewrite, and the reason is worth knowing: a WebM holds VP8, VP9 or AV1, and while an MP4 can technically carry those, almost nothing outside a browser will play them from inside one. So every frame is decoded and compressed again, which takes roughly as long as the video is. The target bitrate comes from the source's own and is never set above it, so the file does not quietly inflate, though it often grows slightly because VP9 is more efficient than H.264 and the same picture needs more bits. Audio in Opus is carried across as it is; Vorbis is re-encoded to AAC.
01 / Your device
the file stays here
02 / Browser memory
the work runs locally
03 / Back to you
saved on this device
When you would use this
Situations, not settings.
- A browser screen recording you want on a phone
- In-page recorders write WebM, which plays in every browser and almost nowhere else. This is the step before it goes to a phone, an editor or a social platform.
- A clip a video editor refuses to import
- Most editing software reads H.264 in an MP4 and shrugs at VP9 in a WebM. The re-encode is real work, and the page says how long before you start.
- Sending something to somebody on an iPhone
- WebM support on Apple devices is patchy enough that MP4 is the safe answer for anything you are handing to a person rather than serving on a page.
How it works / no cloud
A conversion engine, not an upload form.
A WebM holds VP8, VP9 or AV1, and an MP4 can carry those but almost nothing will play them from inside one, so filetity re-encodes the picture to H.264 with the video engine your browser already ships. The target bitrate is taken from the source's own, never above it, so the conversion does not quietly inflate the file.
- Offline ready
- Installable app
- No file limit queue
Straight answers
No accordion. Nothing hidden.
- Is it free?
- Yes, with no watermark and no page limit.
- Does it need an account?
- No. There is no account system.
- Is my file processed on my device?
- Yes. The file is read by your browser and never uploaded. There is no server to send it to.
- What formats are supported?
- WebM in, with VP8, VP9 or AV1 video. MP4 out, H.264 video and AAC audio.
- What are the 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.
- Does it work on mobile?
- Yes, on any modern mobile browser. Large files are limited by the memory the phone gives the browser.
- Does it work offline?
- Yes, once the page has loaded. The tool keeps working with no network connection.
- 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.
Keep working locally
3 available · more coming