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Convert MP4 to WebM

Convert MP4 video files to WebM format for web use, entirely in your browser. WebM is an open-source format with excellent browser support, smaller streaming file sizes, and no patent licensing fees. No server upload, no signup, processed with FFmpeg.wasm.

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MP4, MOV, WebM, AVI · Any format

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Frequently Asked Questions

Why would I convert MP4 to WebM?▼
WebM is an open format with excellent support in all modern browsers. It often produces smaller file sizes than MP4 for equivalent quality, making it ideal for web video embeds.
Is there any quality loss when converting?▼
Minimal quality loss occurs during re-encoding. At high-quality settings the visual difference between MP4 and WebM is imperceptible.
Does the converted WebM support transparency?▼
WebM with the VP8/VP9 codec supports alpha channel transparency. If your source video has transparency, it can be preserved in WebM format.
Is the conversion done in the browser?▼
Yes. FFmpeg.wasm handles the conversion locally. Your MP4 file is never uploaded to any server.
What if I need to convert the other way (WebM to MP4)?▼
Use the video format converter tool on ToolBubble which supports conversion in both directions.