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MP4 to MKV Converter

Convert MP4 videos to MKV format, supporting multiple audio tracks, subtitles, and chapters in a flexible container.

What this tool does

MP4 to MKV Converter helps you convert MP4 videos to MKV format, supporting multiple audio tracks, subtitles, and chapters in a flexible container.

What you get

MP4 to MKV Converter produces a direct output in this page and keeps all processing on your device, with nothing uploaded to our servers.

Free to use, no watermarks, runs in your browser—nothing uploads to our servers

Source file *

Files are processed locally in your browser using WebAssembly. This input is required.

Saved FFmpeg presets (stored locally)

Saved presets

Preset name

Quality (CRF)

Lower = better quality (0-51, default: 23)

Report a bug

If this tool misbehaves, share a quick summary so we can investigate. We include the tool URL automatically—no need to copy and paste.