Convert MP4 to WebM
Turn MP4 videos into open-format WebM files for lightweight web embedding.
Free · No signup · Files never leave your device
Drag and drop a video file
or click to browse
Compatible videos are repackaged in seconds without re-encoding — you'll see whether yours qualifies before converting.
How it works
Drop your MP4 file
It stays on your device — nothing is uploaded.
Converted to WEBM locally
The video is converted right in your browser via WebAssembly. The tool tells you upfront whether it's an instant repackage or a re-encode.
Download the result
Preview the WEBM and download it — free, no watermark.
Frequently asked questions
It depends on the codecs inside your file. When they're compatible with WEBM, the conversion is a near-instant repackage with no quality loss. When they're not, the video is re-encoded in your browser, which takes roughly the video's length. The tool shows you which case applies before you start.
If the video needs re-encoding, a small quality loss is unavoidable, but the converter uses a high-quality setting that is visually indistinguishable for most footage. Compatible streams are copied without any loss.
WebM only accepts VP8/VP9/AV1 video, and MP4 files almost always contain H.264 or HEVC — so the video must be re-encoded, which runs in your browser at roughly the video's length. For long videos, consider trimming first.
Yes. The converter is completely free, with no signup, watermarks, or limits. We make money from our video translation service, not from this tool.
No. The conversion happens locally in your browser using WebAssembly. Your file never leaves your device — you can even disconnect from the internet once the page has loaded.