Free tool
MP4 to MKV converter the container media servers and editors like.
Drop MP4 videos and download MKV versions at the quality you choose, for Plex, Jellyfin, Kodi, OBS and players that prefer Matroska.
MP4 to MKV converter at a glance
content.win converts and compresses video for free, several files at once, and never adds a watermark. You can name an exact size in MB and get a file that fits.
- Works with
- MP4, MOV, WebM and MKV.
- Comes back as
- MP4, MOV, WebM or MKV, at a quality preset or an exact target size in MB.
- Runs
- In your browser.
- Limits
- Up to 10 videos at once, in a browser that can play them. Free space on the device is the only other limit.
- Price
- Free. No account, no watermark.
How to convert MP4 to MKV
- Drop the MP4 videos in. One or several.
- Pick a quality. Best quality keeps the picture as it is; Balanced or a target size makes the file smaller on the way.
- Download the MKVs. Named after the originals.
MKV against MP4
- Same picture, different box
- MKV and MP4 are containers. The video inside can be identical; MKV simply holds more kinds of tracks, subtitles and chapters.
- Where MKV wins
- Media servers, Kodi, VLC and OBS treat MKV as a first-class format, and a recording that stops early still plays.
- Where MP4 wins
- Phones, browsers, Instagram and TikTok take MP4 and often refuse MKV. Convert back with MKV to MP4 when sharing.
Questions people ask
Does MP4 to MKV lose quality?
Not on Best quality, where the picture is kept as it is. Balanced and the target sizes trade a little quality for a smaller file.
Will the MKV play on my phone?
Android with VLC or MX Player, yes. iPhone and web players mostly do not; keep an MP4 for those.
Can I convert several at once?
Yes, up to ten in one drop.
Is there a size limit?
Only the free space on your device.