MP4 to WebM
Convert MP4 to WebM with VP9 or AV1 for smaller, web-ready videos. Great for websites and HTML5 players. Free, no sign-up — runs in your browser, no upload.
- No upload — 100% private
- Instant, on your device
- Free, no sign-up
- Works offline once loaded
How it works
How to use MP4 to WebM
Drop your .mp4 video onto the page.
WebM is pre-selected; pick VP9 (widely supported) or AV1 (smallest) if your browser offers it.
Optionally choose 720p or a bitrate to make it lighter for the web.
Click Convert to WebM and download the result.
Why use it
Why use our MP4 to WebM tool
Web-optimised codecs
VP9 and AV1 deliver the same quality as H.264 at noticeably smaller sizes — ideal for background and hero videos.
Opus audio
Audio is encoded as Opus, the efficient open codec every modern browser plays in WebM.
Only what works
The codec list shows only encoders your browser actually supports, so conversions don't fail halfway.
Private and free
No upload queue and no limits — your MP4 is converted on your own device.
FAQ
Frequently asked questions
Should I use VP9 or AV1?
VP9 encodes faster and plays in every modern browser. AV1 makes even smaller files but is slower to encode and needs newer devices to play smoothly.
Is WebM supported in Safari?
Recent Safari versions play VP9 and AV1 WebM, but older iPhones may not. For a website, offer WebM with an MP4 fallback in the video tag.
Does converting reduce quality?
Converting from H.264 to VP9 or AV1 requires re-encoding. At the default high quality, the difference is hard to see.
Can I keep the video transparent?
MP4 files can't hold transparency, so there's nothing to keep — the WebM will be opaque, just like the original.
Is my MP4 uploaded to convert it to WebM?
No. The conversion to VP9 or AV1 WebM happens locally with your browser's encoder, so you can prepare web-ready videos for your own site without handing the source file to anyone.
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