How do I convert WebM to Matroska (MKV)?

Upload your WebM file using the box above, confirm Matroska (MKV) as the output format, then select Convert. The converted file is ready to download as soon as processing finishes — usually in a few seconds.

Is converting WEBM to MKV free?

Yes, and there is nothing to sign up for. Every conversion is free, there is no paid tier, and the limits are the same for everyone.

Will the quality change when converting to Matroska (MKV)?

MKV uses lossy compression, so some data is discarded to keep the file small. The default quality setting is tuned to be visually or audibly transparent for most material, and you can raise it in the conversion settings.

What happens to my file afterwards?

The uploaded file is deleted as soon as the conversion completes, and the converted file is removed automatically once its retention window ends. Download links are signed and expire within minutes.

webmmkv

Convert WebM to Matroska (MKV)

Free online converter for WebM files. Flexible container for high-quality video. Nothing to install, no watermark, and every file is deleted automatically.

Drag and drop your files

Upload a WebM file to convert it to Matroska (MKV). Up to 200 files at once, 10 GB each.

Free · up to 200 files · 10 GB each · files deleted automatically after 168 hours.

About WEBM and MKV

WebM

Open, royalty-free format optimised for the web.

video/webm

Matroska (MKV)

Flexible container for high-quality video.

video/x-matroska

Other WebM conversions

webm to mp4
webm to mov
webm to avi
webm to gif
webm to mp3
webm to wav
webm to flac
webm to ogg

Other ways to get Matroska (MKV)

mp4 to mkv
mov to mkv
avi to mkv