WebM videos (from browsers and screen recorders) often will not play on iPhones, TVs, editors or social sites. MP4 plays everywhere. This converter runs entirely in your browser — the file is never uploaded.
Why convert WEBM to MP4?
WebM videos (from browsers and screen recorders) often will not play on iPhones, TVs, editors or social sites. MP4 plays everywhere.
How it works
The video is re-encoded to H.264 with AAC audio in an MP4 container. The conversion runs with ffmpeg compiled to WebAssembly, on your device.
Quality notes
Choose a quality level; the High Quality setting keeps it visually identical.
Common use cases
Sharing screen recordings; uploading to sites that reject WebM; editing in software without WebM support.
Frequently asked questions
Why won’t my WebM play on iPhone?＋
Older iOS versions and many apps do not support WebM; H.264 MP4 plays everywhere.
How long does it take?＋
It encodes on your device — seconds for short clips, longer for long ones.
Is my file uploaded?＋
No. The conversion runs in your browser; the file stays on your device.