Compress MKV
Shrink a MKV video's file size — choose the quality, preview the result and download. Runs entirely in your browser; the video is never uploaded.
Input
Higher bitrate = sharper picture, bigger file. The video is re-encoded in real time, so conversion takes as long as the clip.
MP4 video
Upload a MKV video, pick a quality and press Convert to MP4. Everything runs in your browser — the file is never uploaded.
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Guides
What Compress MKV does
Make a big MKV — a camera export, a screen capture, an old download — small enough to email or upload. Pick a lower quality, and the video is re-encoded to a lighter MP4. It runs in your browser, so the video is never uploaded.
How to use it
- Upload a MKV file.
- Pick a video quality (bitrate) — lower means a smaller file.
- Click Convert to MP4, preview the result, then download it.
Good to know
Your browser plays the video and re-records it, so compressing takes about as long as the clip itself — keep the tab open. If the original was already heavily compressed, the result may not shrink much. If a browser can't record MP4, it saves WebM instead and says so. Compression is lossy.
Privacy
Playback and encoding happen on your device. Nothing is sent to a server.