MP4 to WebM converter
Make web-ready WebM video from an MP4, on your own device.
or drop them here, or paste them
Nothing is uploaded.
About MP4 to WebM
WebM uses open, royalty-free codecs and is a good choice for video on your own website. This converter re-encodes your MP4 as VP9 video with Opus sound.
Encoding video takes some work, so give it a moment; the speed depends on your device. Nothing is uploaded.
VP9 usually gives a smaller file than H.264 at the same quality, which saves bandwidth on your own website. Chrome, Edge, Firefox and recent versions of Safari all play WebM, but keep an MP4 as a fallback for older Apple devices.
The WebM keeps the resolution and frame rate of the original. Encoding VP9 is demanding, so a long video can take several times its own length on an older phone; a short clip is ready quickly. If your browser can't encode VP9, the page tells you before you start.
Sound is encoded as Opus, which sounds clear even at low bitrates. If the MP4 has no sound track, the WebM simply has video only. You can convert several MP4 files in one go and download them together as a ZIP.
Questions and answers
For websites: every current browser plays it, and its codecs are free to use. For sharing with people, MP4 is still the safer choice.
Often a little, as VP9 compresses well. It depends on the video; the result shows the size before and after.
Recent versions of Safari play WebM. Older iPhones and Macs may not.