Convert MP4 to MKV Online
Need MKV instead of MP4? This free converter changes MP4 files into MKV in seconds, right in your browser.
How to convert MP4 to MKV
- Upload your MP4 file. Drag it onto the box above or click to browse. Files up to 200 MB are accepted.
- Choose MKV as the output. The target format is pre-selected on this page — just press “Convert now”.
- Download the result. Conversion runs on our own server and the download starts as soon as it is ready. Your files are deleted automatically.
Why convert MP4 to MKV?
MP4 is the universal video container, playable on virtually every device, browser, phone and smart TV. MKV is a flexible open-source container that can hold unlimited video, audio, subtitle and chapter tracks. That difference is exactly why converting between them is so common: MKV is the better choice for movies, TV rips, multi-audio and multi-subtitle releases.
MP4 vs MKV: key differences
| MP4 | MKV | |
|---|---|---|
| File type | lossy container | open container |
| Typical use | streaming, social media, mobile playback, archiving everyday video | movies, TV rips, multi-audio and multi-subtitle releases |
| Compatibility | Near-universal support. Typically pairs H.264/H.265 video with AAC audio. | Supported by VLC, mpv, Plex and most desktop players, but not natively by some mobile devices. |
Tips for a clean MP4 to MKV conversion
- Near-universal support. Typically pairs H.264/H.265 video with AAC audio.
- Use the highest-quality source MP4 you have — converting a compressed file again cannot restore lost detail.
- If you only need a smaller file, try a lower resolution or bitrate instead of a different format.
- Keep the original MP4 until you have checked the converted MKV opens the way you expect.
Frequently asked questions
How do I convert MP4 to MKV?
Upload your MP4 file to the converter on this page, make sure MKV is selected as the output format and click “Convert now”. When the conversion finishes the download starts automatically.
Is this MP4 to MKV converter free?
Yes — it is completely free and needs no account. Files up to 200 MB are accepted, and heavy use is rate-limited so the service stays available for everyone.
Will converting MP4 to MKV reduce quality?
Because both formats preserve the original data, converting back and forth does not degrade quality.
What is a MP4 file?
MP4 is the universal video container, playable on virtually every device, browser, phone and smart TV. Its technical name is MPEG-4 Part 14 and it is typically used for streaming, social media, mobile playback, archiving everyday video.
What is a MKV file?
MKV is a flexible open-source container that can hold unlimited video, audio, subtitle and chapter tracks. Its technical name is Matroska Video and it is typically used for movies, TV rips, multi-audio and multi-subtitle releases.
Can I convert MP4 to MKV on my phone?
Yes. The converter runs in the browser on Android, iOS, Windows, macOS and Linux — no app installation is required.
Are my files kept on the server?
No. Uploaded files and converted results are deleted automatically a short time after the conversion finishes.