shycut

Convert WebM to MP4 on your device

Browser screen recorders and many web downloads save WebM. Drop it here and get an MP4 that the rest of your apps will open.

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Drop your video here

Choose your video

MP4, MOV, WebM or MKV. It opens right here, on your device.

  • Nothing uploaded
  • No sign-up
  • No watermark

Tested in the browser

BrowserResultWhat came out
Google Chrome 155ConvertedMP4: H.264 video, AAC sound, 1280×720
WebKit 27.2 (Safari’s engine)ConvertedMP4: H.264 video, AAC sound, 1280×720

On October 24, 2026, a 10-second 1280×720 WebM (VP9 video, Opus sound) went through this page’s button in each browser, and what came out was read back with ffprobe.

The test file carried a location tag; no converted copy kept it.

When to turn WebM into MP4

WebM is made for the web: it streams well and every major browser plays it. Outside the browser it is less welcome; some editing apps, older phones and messaging apps won’t open it, or open it without sound.

The VP9 or VP8 picture inside is encoded again as H.264 and the Opus sound as AAC, the pairing nearly every device decodes. If you only need part of a recording, open it in the editor instead and cut it before saving.

WebM and MP4, in short

WebM
Google’s open web format, with VP8, VP9 or AV1 video and Opus or Vorbis sound. Browser screen recorders and many downloaded web videos come as WebM.
MP4
The format that plays almost everywhere: phones, browsers, TVs, editing apps and every social platform take it. Inside is usually H.264 video and AAC sound.

How to convert

  1. Open the WebM

    Press the button and drop the file, or pick it from your files. It opens in this browser tab: nothing is uploaded, so there is no upload limit to hit.

  2. MP4 is already chosen

    The save window opens set to it. Change the file name or the quality if you like.

  3. Save

    The new file is written on your device and downloaded. Several files? Drop them together and they are converted one after another.

What changes, what stays

Picture and length
Nothing is cut or reframed: the video keeps its own picture size and runs from start to end.
Sound
The first sound track, at its own level, in stereo at most.
Quality
Small, Balanced or High; Balanced is chosen to begin with.
Details about you
The file is written from scratch, so none of the original’s metadata comes along: no location, no camera or phone model.

Questions

Why won’t my WebM play in my editor or on my phone?

The app has no decoder for VP8, VP9 or Opus, the codecs WebM uses. An MP4 with H.264 and AAC avoids the problem.

Can I convert a recording from a browser extension?

Yes. Recordings made in the browser are usually WebM with a picture and sound, and they convert like any other video.

Will the MP4 be bigger than the WebM?

Often a little, because VP9 fits a picture into fewer bits than H.264 does. Pick Small in the save window if size matters more than detail.

Your video stays with you.

Open Shycut, drop the video in and export. Free, with no account, and your video never leaves your device.

Choose your video

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