WebM is actually based on Matroska, the same family as MKV, but restricted to web-friendly codecs. Converting an MKV to VP9 WebM gives you a video that browsers play natively, ready to embed on any page.
How to convert MKV to WebM (VP9)
- Drop your MKV files in the box above, or click to pick them. You can add as many as you like.
- WebM (VP9) is already selected as the output format. Switch on other formats if you want them too.
- Optional: open Advanced Settings to resize by percentage, width or height, and add more sizes.
- Click Start Conversion, then download each file or all of them at once. Nothing is uploaded: the conversion runs in your browser.
Why convert MKV to WebM (VP9)?
MKV files are not playable in every browser, while WebM with VP9 is designed for the web: compact, open and royalty-free.
Frequently asked questions
Are MKV and WebM the same thing?
WebM is a subset of Matroska limited to web codecs like VP9 and Opus. An MKV can hold almost any codec, so it is not always playable in browsers.
Are my videos uploaded?
No. The video is decoded and encoded in your browser, on your device. Nothing is sent to a server, which also means there is no file size limit other than your device memory.
Can I resize the video while converting it?
Yes. Open Advanced Settings and turn on Resize to scale the video by percentage, width or height. You can add more sizes to get several versions in one go.