Convert any MP4 file to WebM — free, private, entirely in your browser.
Click "Start Converting — Free" to launch the converter in your browser.
Drag and drop your MP4 file or click to browse. Choose WebM as the output format.
Conversion runs locally via WebAssembly. Download your WebM file instantly.
Files never leave your device. MP4→WebM conversion is 100% client-side.
No registration, no watermarks, no usage limits — ever.
Uses open-source FFmpeg compiled to WebAssembly for native-speed conversion.
Works in Chrome, Firefox, Edge, and Safari on desktop and mobile.
Convert multiple files using the built-in queue without reloading the page.
Yes. AnyConvert uses open-source FFmpeg via WebAssembly — no cost, no sign-up, no limits.
No. All conversion happens in your browser using WebAssembly. Your files never leave your device.
There is no server-side limit. The practical limit depends on your device's available memory — most files under 500 MB work fine.
WebM is the preferred open video format for web browsers. It offers excellent quality at smaller file sizes than MP4 for web streaming.
Open AnyConvert in your mobile browser, select your MP4 file, choose WebM as output, and download. No app needed.