About this MP4 to WebM tool
WebM with VP9 video is supported by all modern browsers and often gives smaller files than H.264 at the same quality, which makes pages load faster.
The tool re-encodes the picture to VP9 (or VP8 on older browsers) and the sound to Opus, all on your device.
How to use MP4 to WebM
- Choose or drop an MP4, MOV or MKV video.
- Click Convert video.
- Download the WebM file.
Features
VP9 video
Modern and efficient.
Opus audio
Clear sound at low bitrates.
Private
Nothing is uploaded.
Good to know
- Works in up-to-date Chrome, Edge, Firefox and Safari on computers and Android. iPhones with iOS 17 or newer work too.
- Files up to about 1 GB work well on most computers. Phones handle shorter clips best.
- Only edit videos you own or have permission to use.
Frequently asked questions
Does Safari play WebM?
Yes, Safari 14.1 and newer plays WebM with VP9.
Is WebM smaller than MP4?
Often a little, at the same visual quality.
How long does it take?
Re-encoding runs about as fast as, or faster than, the video's length on a modern computer.
Is my video uploaded?
No. The whole job runs inside your browser using your device's built-in video encoder, so the video never leaves your device.