Convert to WEBM, Free
Upload your MP4 file and get a WEBM in seconds. No account, no watermark.
How to convert MP4 to WEBM
WebM is an open-source video format developed for the web, using the VP8/VP9 or AV1 video codec and Vorbis or Opus audio. WebM files are smaller than MP4 at comparable quality and play natively in all modern browsers without plugins. WebM is the preferred format for HTML5 video on the web.
BoltConverter converts MP4, AVI, MOV, MKV, and other video formats to WebM on its servers. The output is optimized for web delivery and plays directly in browsers without requiring codec installation.
Upload your video file
Click the upload area or drag your video file onto the page.
Conversion to WebM runs on the server
The server re-encodes the video using a web-optimized VP9 or similar codec and wraps it in the WebM container.
Download the WebM
Save the .webm file for embedding on a web page or sharing online.
Frequently asked questions
What is WebM best used for?
WebM is designed for streaming video on websites. It is the standard format for HTML5 video elements and is supported natively in Chrome, Firefox, Edge, and Opera.
Is WebM better than MP4 for the web?
WebM often achieves smaller file sizes than MP4 at similar quality due to the VP9 or AV1 codec. However, MP4 (H.264) has broader device support, including older devices and Safari.
Does Safari support WebM?
Safari historically did not support WebM, but modern versions of Safari on macOS and iOS have added VP9/WebM support. For maximum compatibility, serve both MP4 and WebM.
Can I use WebM for animated images instead of GIF?
Yes. A short WebM clip used with the HTML video element (autoplay, loop, muted) is a much more efficient alternative to animated GIF, with far smaller file sizes.
What codecs does the WebM output use?
The output typically uses VP9 for video and Opus for audio, which are the current standard WebM codecs for quality and efficiency.