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Supports MP4, WebM, MOV, AVI | Max 500MB
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Videos are converted entirely in your browser. Nothing is uploaded to any server.
Uses FFmpeg.wasm for native-speed video processing in browser.
Convert between MP4, WebM, MOV with H.264 encoder support.
See original vs converted file size at a glance.
Convert video format online free with FreeToolBox — transform MP4, MOV, WebM, AVI, MKV, and other video files between formats right in your browser using FFmpeg.wasm. Different platforms have different requirements: Twitter and YouTube prefer MP4 (H.264), web browsers natively play WebM (VP9), and older devices may need AVI. Choose the right output codec for your target platform.
All conversion runs locally in your browser using WebAssembly — your video files are never sent to any server. Privacy is guaranteed. The output video has no watermarks. Completely free, no account required.
MP4 with H.264 codec is the universal standard — compatible with virtually every browser, device, and platform. For modern browsers, WebM with VP9 offers better compression. HEVC/AV1 give the best compression but have limited support.
Re-encoding between lossy formats always involves some quality loss. Converting from a high-quality source keeps the loss imperceptible. Converting lossy-to-lossy multiple times compounds quality loss (generation loss).
No. FFmpeg.wasm converts your video entirely within the browser. Your file stays on your device throughout.
Video encoding is computationally intensive. FFmpeg.wasm runs in a browser thread without GPU acceleration. Shorter clips or lower resolution settings convert faster.