Video
What is an MKV file?
Updated Jul 2026
MKV (Matroska Video) is a flexible container format built to hold high quality video, multiple audio tracks, and subtitles together in one file. It doesn't compress anything itself, it just packages streams as they are, which is why files stay large and detailed. Many phones, TVs, and simpler apps still can't play it directly.
- Extension
- .mkv
- Type
- Video
- Typically
- High-quality video containers
Why MKV exists
MKV takes its name from Matroska, a project started in the early 2000s that wanted one container flexible enough to hold pretty much any combination of video, audio, and subtitles. The name comes from the Russian matryoshka nesting dolls, since a single file can nest many separate tracks inside it.
An MKV file doesn't do the compressing itself, it's a wrapper. The video and audio inside can be encoded at very high quality, and the container can hold several audio tracks at once, different languages or commentary tracks, plus multiple subtitle tracks, all switchable without needing separate files. That's why MKV shows up so often for movie rips, TV downloads, and home media libraries.
The trouble is compatibility. MKV plays well on computers and dedicated media players, but iPhones, many Android phones, smart TVs, and streaming apps often won't open it at all, or only play the video while dropping the extra audio and subtitle tracks. That mismatch is usually why someone needs to convert it, most often to MP4, to get a file that plays everywhere.
The trade-offs
Strengths
- Can hold very high quality, near lossless video and audio
- Bundles multiple audio tracks and subtitle tracks in one file
- Well suited for archiving movies and TV without losing quality
- Widely supported by computers and dedicated media players
Watch-outs
- Large file sizes compared to more compressed formats
- Not supported natively on many phones, TVs, and streaming apps
- Often needs converting to MP4 before it will play everywhere
A note on privacy
MKV files don't usually carry personal metadata like GPS the way photos do, but they're often large, so uploading one to an online converter means sending your whole video to someone else's server and waiting for it to come back. Converting on your own computer keeps the file, and whatever it contains, on your machine the entire time.
Convert an MKV file
- Convert MKV to GIF
- Convert MKV to MP4
- Convert MKV to MOV
- Convert MKV to WebM
- Convert MKV to AVI
- Convert MKV to WMV
- Convert MKV to FLV
- Convert MKV to M4V
Questions
How do I open an MKV file?
On a Mac or Windows PC, most modern media players open MKV directly. On an iPhone or many smart TVs, you'll usually need to convert it to MP4 first.
Is MKV better than MP4?
MKV can hold higher quality and more audio and subtitle tracks, but MP4 is far more widely supported. For playing on a phone or uploading somewhere, MP4 is usually the safer choice.
Why do my downloaded videos save as MKV?
MKV is a common format for movie and TV rips because it can hold high quality video plus multiple audio and subtitle tracks. It's popular with archiving, not something your phone typically chooses on its own.
Can I convert MKV without uploading it?
Yes. A desktop app like Morphjet converts MKV to MP4 or other formats on your own computer, so the video never has to leave your device.
Morphjet opens and converts MKV and 1,800+ other formats, all on your own computer. Launching this July.