Convert WebM to MKV
Turn WebM video files (.webm) into Matroska video (.mkv) in seconds. Drop one file or a whole batch: the conversion happens right in your browser, with no sign-up, no watermark and no upload.
MKV to WebM insteadHow to convert WebM to MKV
- 1Drop your WebM files into the box above, or click to choose them.
- 2MKV is already selected. Adjust the options if you like.
- 3Click Convert and download your MKV files.
Good to know
- When the video and audio codecs are allowed in MKV, the streams are copied without re-encoding, which is fast and lossless. Otherwise they are re-encoded with a quality you choose.
- Large videos are processed as a stream, so even long files work as long as your device has enough memory.
Frequently asked questions
Is converting WebM to MKV free?
Yes. There is no sign-up, no watermark and no limit on the number of files.
Are my files uploaded?
No. Everything runs in your browser, so your files are never uploaded to a server. That also makes it fast, because nothing has to travel over the network.
Will I lose quality converting WebM to MKV?
MKV stores the result with some loss. With the default settings the difference is hard to notice, and you can raise the quality if you need to.
Can I convert several files at once?
Yes. Drop as many WebM files as you like. They are converted one after another and you can download them individually or as a ZIP.
Is there a file size limit?
There is no fixed limit. Very large files depend on your device's memory, since the conversion runs locally.
What is WebM?
WebM is an open web video format using VP8, VP9 or AV1 video with Opus or Vorbis audio.
What is MKV?
MKV is a flexible open container that can hold many video, audio and subtitle tracks.