Free browser tool
MP4 to WebM converter
Convert MP4 to WebM right here on your device. Choose a file, convert it locally, and download the result.
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1. Choose your file
3. Convert and download
Choose your file to begin.
Keep this tab open while converting. Desktop browsers work best. Files stay on your device; available conversions depend on your browser and the codecs inside your file.
Your converted file
Your browser cannot preview this file. You can still download it.
Download converted fileHow to convert MP4 to WebM
- Choose your MP4 file. Files must be under 250 MB and no longer than 10 minutes.
- Pick the output quality and select Convert. Processing runs on your device.
- Preview the result and download your WebM file.
About MP4 to WebM conversion
A video container commonly used for H.264 video and AAC audio.
Creates VP9 or VP8 video with Opus audio when a soundtrack is present. Compatible tracks can be copied at original quality.
Original quality copies compatible tracks where possible. Other tracks are re-encoded. Smaller file quality re-encodes the video within 720p and 30 frames per second. Video conversion supports up to 4K SDR; HDR video is rejected to avoid changing its colors.
Questions about this converter
Does my file leave my device?
No. The page downloads the conversion software, then reads and processes your selected file locally. There is no media upload or server conversion fallback. The site's ordinary cookie and analytics preferences still apply.
Why might a file fail to convert?
A filename extension describes a container, which can hold different codecs. The browser must support decoding the actual source tracks and encoding the selected output. Protected, damaged, and unsupported files receive an error. Try another supported desktop browser if a codec is unavailable.
Will quality or file size change?
Re-encoding can lose detail. Compatible video tracks may be copied at original quality; MP3 is re-encoded and WAV is exported as 16-bit PCM. Converting a compressed recording to WAV does not recover missing detail. Output size is limited to 250 MB and may be larger than the input.
Are all tracks and metadata kept?
Only the primary video and audio tracks are used. Audio outputs discard the video. Re-encoded audio is mono or stereo; compatible audio copied into a video keeps its channel layout. Additional soundtracks, subtitles, chapters, descriptive tags, and attachments are not carried over. The tool stops if it cannot retain a required primary track.
Can I convert on a phone?
The tool is designed for supported desktop browsers. Some phones may work, but codec support, memory, and background tab restrictions vary. The tool processes one file at a time.