MP4 to MKV converter

Remux MP4 into MKV with stream copy — keeps the same video and audio quality, often faster than full transcode. Requires FFmpeg on the server. Free, no registration.

MP4 in MKV out HTTPS

Drop your MP4 here

or browse — up to 150 MB • MP4 only • stream copy • FFmpeg on server

How to convert MP4 to MKV

1

Upload MP4

Drag and drop or pick an .mp4 file up to 150 MB.

2

Remux

We copy streams into an MKV container with FFmpeg (-c copy).

3

Download MKV

Save the MKV for players and tools that prefer Matroska.

Why remux MP4 to MKV?

Change container without losing quality.

Stream copy

No re-encoding — same quality, usually faster than transcoding.

MKV container

Matroska supports multiple tracks and is popular in media libraries.

No install

Remux in the browser when FFmpeg is available on the server.

Need AVI instead? Try MP4 to AVI.

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