WebM to MP4 Converter

Why convert WebM to MP4?

WebM is Google's royalty-free video format — excellent for the web, and the default for many screen recorders, browser downloads, and video calls saved from Chrome. The problem starts the moment the file leaves the browser: iPhones and Safari have historically refused to play WebM, Instagram and TikTok won't accept it for upload, many desktop video editors can't import it, and some smart TVs just show a black screen. MP4 with H.264, by contrast, plays on literally everything made in the last fifteen years.

Converting doesn't mean losing quality. WebM (VP8/VP9) and MP4 (H.264) are both modern codecs; a careful re-encode preserves essentially all visible detail while buying you universal compatibility. That is exactly what this tool does.

How to convert WebM to MP4 (3 steps)

1. Select your WebM file. Click the box or drag it in. It is read directly by your browser — nothing uploads.
2. Convert. One click. The video is re-encoded to H.264 + AAC in MP4, the most compatible combination in existence.
3. Download. Save your MP4. It plays on iPhone, Android, Windows, Mac, browsers, and TVs — and uploads anywhere.

Private by design: nothing is uploaded

This tool runs FFmpeg, the industry-standard video engine, compiled to WebAssembly and executed entirely inside your browser tab. Your video never travels over the network — check your browser's network tab if you like. It is safe for private clips and works on slow connections, because only the ~30MB engine downloads once.

WebM vs MP4: what is the difference?

Both are containers holding video and audio streams. WebM typically carries VP8/VP9 video with Opus or Vorbis audio — open, royalty-free, and great inside Chrome and Firefox. MP4 typically carries H.264 video with AAC audio — patented, but supported by every device, editor, and platform on earth. For archiving or web embedding, WebM is fine. For sharing, editing, or uploading to social platforms, MP4 wins every time. File sizes are comparable; compatibility is not.

One note: if your WebM already plays fine everywhere you need it, don't convert — every re-encode loses a tiny amount of quality. Convert when compatibility demands it, which, for WebM, is often.