Convert MP4 to MKV
Same codecs, Matroska container: instant, lossless conversion.
Your files never leave your device
How to convert MP4 to MKV
- 1
Upload the MP4
The video to convert.
- 2
Convert
Streams are copied into the Matroska container.
- 3
Download the MKV
Identical quality, in seconds.
Why use this tool
Lossless
Bit-for-bit stream copy: zero recompression.
Flexible container
MKV holds nearly any codec, subtitles and chapters.
Instant
Only the container is rewritten.
Private
The video never leaves your device: ffmpeg runs in your browser.
Frequently asked questions
Why convert to MKV?
For Matroska-first workflows: adding external subtitles, chapters, or storing in a more flexible container.
Is quality lost?
No: the H.264/AAC streams are copied without re-encoding.
Does MKV play everywhere?
MKV works in VLC and desktop players; old phones and TVs struggle. For maximum compatibility, stay with MP4.
Why is it instant?
Because only the video's wrapper is rewritten, not its content.