Convert MP4 to WebM
Free, private, and entirely in your browser — no upload, no account, no watermark.
The converter opens with WebM already chosen as the output. Just drop your MP4 file and convert — nothing uploads.
How it works
Tap the button above — WebM is pre-selected as the output format.
Your file stays on your device. Wait for the green “Engine ready” banner on first use.
Click Convert, then download your WebM file straight to your device.
About MP4, and why convert to WebM
WebM is the web-native container: VP9 video with Opus audio, open and royalty-free, built for playing straight inside a browser page. It is what many websites serve when they want video without licensing baggage.
If you are putting video on a website, WebM is often the smallest file that still looks good, and it plays natively in Chrome, Firefox and Edge. For a page that loads fast, WebM beats MP4 at the same quality.
Quality guidance for this conversion
VP9 at Balanced quality is the sweet spot for the web: visibly close to the MP4 at a smaller size. If the video is mostly still (slides, screencasts), the savings are biggest; fast action saves less. Keep the original resolution — VP9 does the shrinking, not a resolution cut.
Frequently asked questions
Is WebM really smaller than MP4?
Often, yes — VP9 compresses more efficiently than H.264, so the same quality usually comes out smaller, especially for screen content.
Will it play in all browsers?
Chrome, Firefox and Edge play WebM natively, and recent Safari does too. For maximum reach, keep the MP4 as well and serve both.
Can I edit WebM in my video editor?
Not all editors accept it — that is WebM’s weak spot. If you plan to edit later, keep the MP4 original and export WebM only for publishing.
Does the audio survive?
Yes, the audio is converted along with the video.