Online File Tool
MP4 to WebM Online — Convert Video in Your Browser
Convert MP4 video to VP9/Opus WebM on your device. Choose files up to 25 MB and check output compatibility, quality and file size.
Drop files here or choose from your device
Max. 25 MB/file · Files are processed on your device.ADVERTISEMENTSponsor space
How to use this tool
- Select an MP4 video up to 25 MB without DRM.
- Process it and wait for the video engine to load. Keep the page open during conversion.
- Download the WebM and check picture, sound and playback duration.
Frequently asked questions
Why do some MP4 files fail to convert?
MP4 is a container that can hold different codecs. Unsupported codecs, damaged files or the processing time limit can cause failures. Try a shorter clip.
Is WebM always smaller than MP4?
No. The output uses VP9 video and Opus audio; size and quality depend on the source and encoder settings. A specific compressed size is not guaranteed.
Process files on your device
This tool processes file contents in your browser without uploading documents to a conversion server. Download the result before closing the page and keep the original for comparison.