Convert MP4 to MKV Online
Upgrade your video container. Convert MP4 to MKV to support soft subtitles (SRT/ASS), chapters, and multiple audio languages in one file.
Why Convert MP4 to MKV?
MP4 is an excellent format for playback and streaming, but it has limited support for advanced features like multiple subtitle tracks, chapter markers, and alternate audio streams. MKV (Matroska) can hold virtually unlimited video, audio, picture, or subtitle tracks within a single container file.
This makes MKV ideal for anime fans, movie collectors, and media archivists who want to preserve original Japanese audio alongside English dubs, embed styled ASS/SSA subtitles, and maintain chapter markers without permanently burning them into the video stream.
How to Convert MP4 to MKV
- Upload your MP4.
- We repackage it into MKV.
- Download availability depends on file size.
Key Features of MiConvert MP4 to MKV
- Convert MP4 to MKV for advanced features
- Support for subtitles and chapters
- High-quality video conversion
- Fast, free, and secure
- No software installation needed
- Batch processing supported
Frequently Asked Questions
Is re-encoding needed?
Usually no. We can just copy the video stream into the MKV container, which is instant and maintains 100% quality.
Does it play on VLC?
Yes, VLC, MPC-HC, PotPlayer, and most modern media players handle MKV files perfectly with full subtitle and multi-track support.
Can I add subtitles later?
Yes, MKV makes it easy to add, remove, or swap subtitle tracks later using free tools like MKVToolNix without re-encoding the video.
Is it free?
Yes, our MP4 to MKV converter is completely free to use online with no registration required, no watermarks, and no daily limits.