MKV to WEBM Converter
Free Online MKV to WEBM Converter
Convert MKV (Matroska) video files to web-friendly WebM format instantly in your browser — no software to install, no registration, and no watermarks. Uploaded files are automatically deleted after one hour.
Why convert MKV to WebM?
MKV is a powerful container for storing movies with multiple audio and subtitle tracks, but it is not supported by web browsers. WebM (VP9/Opus) is designed specifically for HTML5 video playback and is supported by Chrome, Firefox, Edge, and Opera. Converting MKV to WebM lets you embed your videos directly on websites without relying on plugins or third-party players.
Quality settings
The CRF (Constant Rate Factor) value controls quality versus file size. Lower values produce better quality but larger files. The default of 30 works well for most web content. Use 20–25 for higher quality or 35–45 for smaller files.
Frequently asked questions
Will subtitles be preserved?
WebM has limited subtitle support. Soft subtitles in SRT or ASS format embedded in the MKV will not carry over to WebM. If you need subtitles, consider burning them into the video using our video subtitle tool before converting.
What is the maximum file size?
You can upload files up to 200 MB. For larger files, try trimming the video first.
Similar conversions: MKV to MP4, MKV to MOV, WebM to MKV.