WebM to MKV Converter
Convert WebM video to MKV in your browser — no upload, no watermark.
To convert WebM to MKV, drop your video in and choose a quality. The conversion runs through FFmpeg compiled to WebAssembly inside your browser, so the file is never uploaded and there is no size cap beyond your available memory. MKV is a container rather than a codec — it holds almost any stream, plus multiple audio tracks and subtitles, which is why it is common for archived media.
Runs in your browserAbout converting WEBM to MKV
MKV is a container rather than a codec — it holds almost any stream, plus multiple audio tracks and subtitles, which is why it is common for archived media. Because the encode happens on your own machine, expect roughly real-time speed for 1080p — a five-minute clip takes about five minutes. That is the trade for not uploading it.