MP4 to WebM
Convert MP4 to WebM online, free — right in your browser. Nothing is uploaded.
Everything ran in your browser — nothing was uploaded.
How to use the MP4 to WebM
- Drop in your MP4 video.
- The output is already set to WebM.
- Click Process and download your WebM video.
About the MP4 to WebM
MP4 to WebM converts MP4 video into WebM, right in your browser. MP4 (H.264) is the universal video format — it plays on every phone, browser, TV, editor and social platform, which makes it the safe default for sharing. WebM is the open, royalty-free web video format — smaller files that play in every modern browser, ideal for websites.
Converting MP4 to WebM gives you an open, royalty-free video that loads fast on websites and plays in all modern browsers. The video is re-encoded to the target codec at high quality; converting cannot add quality the source never had, so start from the best original you have. Everything runs on your device with a WebAssembly build of ffmpeg, so your video is never uploaded — it is private, free and has no watermark. These tools are best for short clips, since the work runs on your device; the engine downloads once (about 25 MB) and is then cached.
Frequently asked questions
Is my video uploaded?
No. The conversion runs entirely in your browser with ffmpeg (WebAssembly). Your video never leaves your device.
Will converting MP4 to WebM lose quality?
The video is re-encoded to the target codec at high quality; converting cannot add quality the source never had, so start from the best original you have.
Why is it slow on long videos?
The work happens on your own device rather than a server, so long or high-resolution clips are demanding. Trim first or use a shorter clip for best results.
Is there a watermark or sign-up?
No. It is completely free, needs no account, and never adds a watermark.