MP4 to WebM free

For video on a website, WebM is usually 20 to 40 percent smaller than the same MP4 at the same quality, and every modern browser plays it. This page encodes an MP4 to WebM with VP9 video and Opus audio on your device, so a hero background or a product clip loads faster without a server-side pipeline.

Drop a video here MP4, MOV, WebM, MKV, 3GP · up to a few GB on a laptop, ~500 MB on a phone · nothing is uploaded

Choose a video

Smaller files for the web

VP9 at the same visual quality is markedly smaller than H.264, which is why YouTube serves it.

Pick the size

Keep the resolution for a hero video or drop to 720p for a thumbnail loop; quality presets control bitrate.

Nothing uploaded

Encoding runs in your browser with WebCodecs. Your footage stays on your machine.

Frequently asked questions

Should I serve WebM or MP4?

Both: WebM first, MP4 as the fallback in a <video> element with two <source> tags. Safari on older iOS needs the MP4.

Why is encoding slower than MKV to MP4?

Because WebM needs a full re-encode to VP9; there is no remux path from H.264. A modern laptop manages near real time at 1080p.

Does it keep audio?

Yes, as Opus at 128 kbps. For a muted background loop, remove the audio in your page's video tag or re-encode without it.

Is anything uploaded?

No. The file is processed in your browser on your own device. Nothing is sent to a server, nothing is stored, and it works offline once the page has loaded.