Convert WebM to MKV
Free, fast WebM-to-MKV conversion.
Video and audio are processed with ffmpeg in your browser — large files are slow and use a lot of memory. Keep files under a few hundred MB for best results.
About the WebM and MKV formats
WebM. WebM is an open, royalty-free video format optimised for the web.
MKV. Matroska (MKV) is a flexible open container holding video, audio and subtitles.
Frequently asked questions
How do I convert WebM to MKV?
Drop your WebM files into the box above and click Convert. The MKV file is generated instantly and ready to download.
Will the quality stay the same?
MKV keeps full quality, so your converted file looks identical to the original.
Is WebM to MKV conversion free?
Completely free, with no sign-up, watermarks or file-size paywalls.