WebM to MP4
Convert WebM to MP4 online, free — right in your browser. Nothing is uploaded.
Nothing is uploaded — this runs on your own device. Which is why the speed is your computer’s: a faster processor and more memory finish sooner, and a large file on a modest machine can take a few minutes. Please leave this tab open while it works.
Everything ran in your browser — nothing was uploaded.
How to use the WebM to MP4
- Drop in your WebM video.
- The output is already set to MP4.
- Click Process and download your MP4 video.
About the WebM to MP4
WebM to MP4 converts WebM video into MP4, right in your browser. WebM is the open, royalty-free web video format — smaller files that play in every modern browser, ideal for websites. 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 great on the web but many editors and phones reject it — MP4 is the safe, universal choice. 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 WebM to MP4 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.