Convert MP4 to WebM Online Free
Runs 100% in your browser — your files never leave your device.
WebM shrinks web video nicely and every modern browser plays it natively. Convert an MP4 to WebM without uploading typical files — the heavy ones are processed by our servers — delete them right after processing, or let them auto-delete within an hour. Perfect before embedding clips on a site.
How it works
- 1
Add your file
Drop your file in or click to browse. Small files never leave your device.
- 2
Convert
Large files automatically finish on our servers instead — delete them right after processing, or let them auto-delete within an hour.
- 3
Download
Save the result instantly — original quality preserved as much as the format allows.
About this tool
Converting MP4 to WebM
MP4 is the universal video container — H.264 video and AAC audio in a package every device, browser, and platform plays. WebM is the web-optimized container built on open codecs — designed for embedding in browsers. Converting re-wraps (and where needed re-encodes) the video into the target container: WebM embeds in web pages efficiently with open codecs.. The conversion runs in your browser for typical files, with larger ones finishing on our servers and auto-deleting within an hour.
What to check after converting
Play the result end to end — container conversions occasionally shift timing or drop a compatibility feature the source container allowed. Check that audio plays in sync and the video renders at full quality, and keep the original file untouched as your master.
Frequently asked questions
Does converting between containers reduce quality?
Re-wrapping a video without re-encoding is lossless; where the target codec requires re-encoding, a small quality step applies. The tool handles both cases transparently.
Is my video uploaded anywhere?
Small videos convert entirely in your browser. Larger ones process on our servers and auto-delete within one hour — nothing is kept.
Why would I choose WebM over MP4?
WebM embeds in web pages efficiently with open codecs.