WebM to MP4.
Turn WebM recordings and downloads into MP4 that plays everywhere. Files stay on your device.
Drop WebM files here or click to browse
Up to 2 GB each · several at once
100% Private
Your files are converted entirely in your browser. Nothing is uploaded.
Plays Everywhere
H.264 video and AAC audio: the MP4 every phone, browser and editor opens.
No Limits
Convert as many files as you want. No daily caps, no watermarks.
How to convert WebM to MP4
- Drop one or more WebM files into the drop zone, or click it to browse your files.
- Click Convert to MP4 and watch the progress bar on each file.
- Click Download MP4, or Download All when you converted several files.
- The MP4 keeps the same name, with .mp4 at the end.
Questions
Are my files uploaded to a server?
No. The converter runs FFmpeg, compiled to WebAssembly, inside your browser. Your files stay on your device. The first run has to load FFmpeg, so it takes a moment to start.
Why convert WebM to MP4?
WebM is common for screen recordings and browser downloads, but many phones, editors, and social apps want MP4. The MP4 you get uses H.264 video and AAC audio, which almost everything plays.
Will I lose quality?
The video is re-encoded at CRF 23, a setting that keeps it looking very close to the original. Sound is kept and converted to 128 kbps AAC.
Which files work, and how big can they be?
WebM files up to 2 GB each, and several at once. Other videos and GIFs work too. Long or very large files take longer, because your own computer does the work.