When to convert MP4 to MKV
Use MKV when a desktop player, media library, archive, or editing workflow prefers the open Matroska container. Keep MP4 when browser and mobile compatibility is the main goal.
MP4 to MKV converter
Upload an MP4 video and convert it to MKV.
MKV
Your converted file will appear here.
Convert MP4 to MKV online
MKV output is helpful when a player or workflow prefers the Matroska container.
- Convert MP4 videos to MKV.
- Create Matroska video files for MKV-compatible players.
- Download the converted MKV after processing.
What the MKV contains
The MP4 is decoded and re-encoded as H.264 video with AAC audio and the yuv420p pixel format inside a Matroska container. The process does more than change the filename extension.
Subtitles and additional tracks
MKV can hold subtitles, chapters, attachments, and multiple audio tracks, but this conversion is designed for the main video and audio output. Do not rely on it to preserve extra MP4 streams or metadata.
Quality and file size
Re-encoding can alter quality and file size. Moving an MP4 into an MKV container does not by itself improve the picture, restore source detail, or guarantee a smaller download.
Frequently asked questions
Can I convert MP4 to MKV online?
Yes. Upload an MP4 file, choose MKV, and download the converted video.
Are subtitles preserved in the MKV?
Extra subtitle, chapter, attachment, and alternate-audio streams should not be expected to carry over.
Which codecs does the MKV use?
The output uses H.264 video and AAC audio in a Matroska container.