MP4 to MKV Converter
Repackage MP4 as MKV without re-encoding a frame.
Free · No upload · No sign-up · No watermark
How to convert MP4 to MKV
- 01
Open your MP4
Drop the MP4 — or any other video.
- 02
Keep MKV selected
It's already chosen. Pick a part if you like.
- 03
Convert and download
Picture and sound are copied, so it takes seconds.
Why use Cutlia for this
Lossless in seconds
H.264, HEVC, VP9 and AV1 are copied into the MKV untouched.
For media players
VLC, Plex, Kodi and Jellyfin all handle MKV well.
Sound copied
AAC, MP3, Opus, Vorbis and FLAC sound is kept as it is.
Frequently asked questions
Why convert MP4 to MKV?
Some media servers, players and archiving setups prefer MKV. The video inside stays exactly the same.
Is MP4 to MKV lossless?
Yes: picture and sound are copied as they are, nothing is re-encoded.
Is my video uploaded to a server?
No. Cutlia processes your video directly in your browser using WebAssembly and your device's hardware. The file never leaves your computer or phone, so it stays completely private.
Is it really free?
Yes. Cutlia is free to use with no account, no trial and no watermark on your export. The site is paid for by the ads on it, and your files never leave your device.
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Each is this converter with the format already picked — and it still opens any video.