How to convert MP4 to MKV
To convert MP4 to MKV, upload your MP4 file, choose MKV as the output format and press Convert. The finished MKV file is ready to save to your phone or computer in seconds, free, with no watermark and no sign-up. Your file is deleted from our server about 30 minutes after the conversion.
This free online converter turns MP4 videos into MKV files in your browser, with no software to install and no watermark. When the video and audio inside your MP4 file can be placed in MKV as they are, the streams are copied without re-encoding, which is faster and keeps the original quality. Otherwise the video is re-encoded as H.264 video with AAC audio.
What you get with MP4 to MKV
- Stores many audio tracks, subtitles and chapters
- Supports almost every codec
- Open and royalty-free
- Plays on: VLC, Plex, Kodi, most Android players and modern Windows; limited on iOS and older TVs
What to expect from this conversion
- Expect a file of similar size to the MP4 original.
- The first audio track is kept. Subtitle tracks, extra audio tracks and chapters are not included in the converted file.
MP4 vs MKV
| Property | MP4 | MKV |
|---|---|---|
| Full name | MPEG-4 Part 14 | Matroska Video |
| Released | 2001, ISO/IEC (MPEG) | 2002, Matroska.org (open standard) |
| Generation | Modern | Modern |
| Typical file size | Small | Small |
| Plays on | Windows, macOS, Android, iOS, smart TVs, game consoles and every major browser | VLC, Plex, Kodi, most Android players and modern Windows; limited on iOS and older TVs |
| Best for | uploading to YouTube, Instagram, TikTok and WhatsApp; sharing a video that has to play everywhere | movie and TV archives with multiple languages; keeping subtitles inside the file |
Steps to convert MP4 to MKV
- Drop your MP4 video file onto the converter, or click to choose it.
- Check that MKV is selected as the target and adjust the options if you want.
- Press Convert, then download your new MKV file when it finishes.
Tips for the best result
- Leave Fast mode on to keep the original quality whenever the streams can be copied.
- Pick a lower resolution if the file is for a phone or messaging app.
- Use Mute if you only need the picture.
Frequently asked questions
How do I convert MP4 to MKV?
Upload your MP4 file, make sure MKV is the selected target and press Convert. When the progress bar finishes, download the MKV file. No account or software is needed.
Is the MP4 to MKV converter free?
Yes. It is free, with no watermark, no sign-up and no daily limit on how many files you convert. The site is supported by ads.
Will I lose quality when converting MP4 to MKV?
Not necessarily. If the video and audio streams already fit inside MKV, they are copied without re-encoding, so quality stays identical. If the file has to be re-encoded, the High setting keeps almost all visible detail, while Small trades some detail for a smaller file.
Will the MKV file be a similar size to my MP4?
Expect a file of similar size to the MP4 original. Choosing a lower quality or resolution reduces the size further.
Which devices can play MKV files?
MKV files play on VLC, Plex, Kodi, most Android players and modern Windows; limited on iOS and older TVs.
How large a file can I upload?
You can upload videos up to 500 MB. Files are deleted from the server about 30 minutes after conversion.