Convert MP4 videos to WebM for smaller file sizes and efficient web delivery. WebM (VP8/VP9) is ideal for HTML5 video. Processing runs locally in your browser.
拖放文件到此处，或
MP4 · MOV · WebM · MKV · AVI
WebM with VP9 encoding often produces smaller files than H.264 MP4 at similar quality, reducing bandwidth costs and improving page load times for embedded video.
WebM is natively supported by all modern browsers. Use it as a primary or fallback source for HTML5 video elements alongside MP4.
The conversion runs on your device. Videos for client projects and internal use never leave your browser.
Create WebM versions of product demos and hero videos for faster page loads.
Website videoReduce CDN and hosting costs by serving smaller WebM files to supported browsers.
Bandwidth savingsUse royalty-free WebM for open-source projects and platforms that prefer open codecs.
Open format publishing关于此工具、支持流程和本地浏览器处理的常见问题回答。
Yes. LessMB converts MP4 to WebM for free in your browser without an account.
WebM often achieves smaller file sizes and is royalty-free, but MP4 has broader device support. Many sites serve both formats.
Yes, all modern browsers (Chrome, Firefox, Safari, Edge) support WebM playback natively.