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FREE MP4 TO WEBM CONVERTER

Convert MP4 to WebM.
Make a web-ready video.

Re-encode MP4 videos as WebM files with this free online tool. Select a video and convert it on your device—your source file is not uploaded.

Drop an MP4 video here

or choose an MP4 file from your device

MP4 INPUT · LOCAL VIDEO ENCODING

The FFmpeg WebAssembly engine (about 31 MB) loads when you start converting. Video encoding uses your device and may take longer than the video's duration. The engine is fetched from a CDN. Each batch is limited to 100 MiB to protect browser memory.

How to convert MP4 to WebM

  1. Select or drop an MP4 video.
  2. Choose Convert MP4 to WebM and wait while your browser re-encodes it.
  3. Download the finished WebM video.

MP4 and WebM video formats

MP4 and WebM are containers for audio and video streams. This converter re-encodes the first video and audio streams using VP8 and Opus codecs to create a WebM file. Conversion time depends on video length, resolution, browser, and device performance.

MP4 to WebM FAQ

Will the converted WebM be smaller?

Not necessarily. Output size depends on the input, codecs, and encoding settings. Check the result before using it.

Are MP4 videos sent to a server?

No. The selected video is encoded locally in your browser. The conversion engine is downloaded from a CDN.

Can every MP4 be converted?

No. MP4 files may contain many codecs; damaged or unsupported media streams can fail to decode or encode.

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