What is an MKV file?
MKV stands for Matroska video. It was created by the Matroska project and first released in 2002. MKV can hold unlimited audio tracks, subtitle tracks and chapters in one file, which is why film rips use it. OBS offers MKV recording because a crash part way through does not corrupt the whole file.
| Type | video |
|---|---|
| Compression | Lossy |
| Usually contains | almost any codec, often H.264 or H.265 with several audio and subtitle tracks |
| In a browser | Chrome and Edge play many MKV files; Safari and iPhones do not |
| Common uses | films and TV rips, OBS recordings and anime releases |
| MIME type | video/x-matroska |
Which format should you convert MKV to?
- MKV to MP4 to play on any phone, computer or TV, or to upload to YouTube and social media.
- MKV to MOV to edit in iMovie or Final Cut Pro on a Mac.
- MKV to MP3 to keep only the soundtrack, for music or a podcast.
- MKV to GIF to share a short silent clip that loops anywhere.
- MKV to WebM to embed on a web page with a small file size.
MKV is already lossy, so converting it to a lossless format makes the file bigger without improving it; pick a lossless target only if a program requires one.
How to open an MKV file
Whether an MKV file opens with a double click depends on the device. Here is what works on each, without buying software:
| Windows | Films and TV and Media Player open the common formats; VLC opens almost any video file, MKV included. |
|---|---|
| Mac | QuickTime Player opens formats Apple supports; VLC or IINA open the rest. |
| iPhone and iPad | The Files app plays formats Apple supports. For others, a player such as VLC for iOS, or converting the file here, is the easiest route. |
| Android | Most gallery and music apps play the common formats; VLC for Android plays almost everything. |
| Web browser | Chrome and Edge play many MKV files; Safari and iPhones do not. |
Want the technical details? See what a .mkv file is, with its MIME type, file signature and a viewer.
MKV compared with other video formats
How MKV stacks up against the formats people most often convert it to or from:
| Format | Compression | Usually contains | Released | Best for |
|---|---|---|---|---|
| MKV | Lossy | almost any codec, often H.264 or H.265 with several audio and subtitle tracks | 2002 | films and TV rips, OBS recordings and anime releases |
| MP4 | Lossy | H.264 or H.265 video with AAC audio | 2001 | phone videos, YouTube uploads, social media and streaming |
| MOV | Lossy | H.264, HEVC or ProRes video with AAC audio | 1991 | iPhone recordings, Final Cut Pro and screen recordings on Mac |
| WebM | Lossy | VP8, VP9 or AV1 video with Vorbis or Opus audio | 2010 | web video, screen recorders and browser-based recordings |
| AVI | Lossy | MPEG-4 Part 2 (Xvid, DivX), MJPEG or uncompressed video with MP3 or PCM audio | 1992 | older camcorders, digital cameras and legacy video libraries |
How to use the MKV converter
- Choose the format you want in the Convert to menu.
- Drop your MKV files on the box, or press Choose MKV files. Several files can go in at once.
- Adjust the settings if you need to; the defaults suit most people.
- Press Convert and save each file with its Download button. Nothing is uploaded at any point.
Tips for converting MKV files without losing quality
MKV is lossy, so some detail was already discarded when the file was made. Converting it cannot bring that back. Converting to a lossless format preserves what is left exactly but makes the file larger; converting to another lossy format adds a small extra loss, which is invisible at sensible settings.
- Keep the original recording. Every re-encode costs a little detail, so convert from the best copy you have, not from a file that was already converted.
- Know whether you need a new container or a new codec. MOV, MKV and MP4 can all hold H.264 video, and switching between them is fast and lossless; changing the codec means re-encoding, which is slower.
- For sharing, MP4 with H.264 at 1080p or 720p is the safe choice: every phone, browser and social network plays it.
- Phones record at very high bitrates. If a file is too big to send, lowering the resolution to 720p usually shrinks it far more than any quality setting.
Convert MKV files from the command line
Everything this page does can also be done in a terminal. The most common MKV conversion, to MP4, looks like this with ffmpeg:
ffmpeg -i input.mkv -c:v libx264 -crf 23 -preset veryfast -c:a aac -b:a 128k -movflags +faststart output.mp4Change the output extension to pick another format. The converter above runs the same ffmpeg engine inside your browser, so you get the result without installing anything.
MKV converter FAQ
What is an MKV file?
MKV stands for Matroska video, a video format created by the Matroska project in 2002. MKV can hold unlimited audio tracks, subtitle tracks and chapters in one file, which is why film rips use it. OBS offers MKV recording because a crash part way through does not corrupt the whole file.
How do I open an MKV file?
Chrome and Edge play many MKV files; Safari and iPhones do not. If the program you need will not open it, convert it to a more widely supported format above.
What is the most common MKV conversion?
MKV to MP4 is the conversion people search for most. If the video inside the MKV is already H.264, the tool first copies the streams straight into the MP4. That takes seconds and loses nothing.
Does converting MKV files here upload them?
No. Every conversion on this page runs inside your browser, so your MKV files never leave your device.
Is the MKV converter free?
Yes. There is no sign-up and no watermark, and no limit on how many MKV files you convert. The site is supported by advertising.
Can I convert MKV files on iPhone or Android?
Yes. Open this page in Safari on iPhone and iPad, or in Chrome on Android, choose your MKV files and download the results to your Downloads folder.
Can I convert several MKV files at once?
Yes. Drop as many as you like; they are converted one after another, each with its own download button.