Free tool

WebM to MP4 converter screen recordings that play everywhere.

Drop a WebM from a screen recorder, a browser or a chat export and download an MP4 that plays on iPhone, imports into any editor and uploads anywhere.

WebM to MP4 converter at a glance

content.win compresses big files for free, several at once, and never adds a watermark. You can name an exact size in MB and get a file that fits.

Works with
MP4, MOV, WebM and MKV.
Comes back as
MP4, MOV, WebM or MKV, at a quality preset or an exact target size in MB.
Runs
In your browser.
Limits
Up to 10 videos at once, in a browser that can play them. Free space on the device is the only other limit.
Price
Free. No account, no watermark.

How to convert WebM to MP4

  1. Drop the WebM in. Loom, Chrome and OBS recordings, Discord and Telegram exports.
  2. Keep the quality, or shrink it. Format is already MP4. "Best quality" keeps the picture; a target size makes it smaller for sharing.
  3. Download the MP4. H.264 video, which every device and editor accepts.

Where WebM comes from and why it gets stuck

Browser recorders
Chrome, Loom, Google Meet and most in-browser recorders save WebM, because that is the format browsers can write. Outside the browser it is far less welcome.
iPhone and iPad
iOS does not play WebM. The MP4 does, in Photos, iMessage and every app.
Editors and platforms
Premiere, Final Cut and many upload forms refuse WebM. MP4 imports cleanly.

What changes inside the file

  • WebM holds VP8 or VP9 video with Opus or Vorbis audio. The video is re-encoded to H.264, which every device plays, at a high quality that looks the same.
  • Screen recordings with a missing duration, which browser recorders often produce, are repaired on the way through so the MP4 scrubs and seeks correctly.

Questions people ask

Does WebM to MP4 lose quality?

The video is re-encoded, since MP4 cannot hold VP9, but at a high quality that is visually identical for screen recordings and talking heads. Choosing a smaller size trades quality for size on purpose.

Why does my WebM show no length or refuse to seek?

Browser recorders write the file before they know its length. The MP4 from this tool has a proper index, so it seeks and shows its duration everywhere.

Will it play on iPhone?

Yes. The MP4 uses H.264 video, which iOS plays natively.

How big can the file be?

As big as you like; free space on the device is the only limit.

Can I make it smaller at the same time?

Yes. Pick a target size or "Balanced" instead of "Best quality".

Is there a watermark?

No.