Convert MKV to MP4
To convert an MKV to MP4, drop the .mkv into the converter above and click Convert to MP4; the file downloads when it is ready. Re-encoding a video is more than a browser can do for a large file, so it is sent to our server over an encrypted connection, converted, and then deleted. The output is a standard MP4 (H.264 video, AAC audio) with broad device support.
Encrypted upload on an EU server, deleted within about an hour.
Drop your MKV hereChoose a MKV to convert
It becomes a MP4 right in your browser, up to 500 MB
Limits, published exactly
| Where it runs | On our server, over an encrypted connection; deleted within about an hour. |
|---|---|
| Free conversions | 2 per day without an account, 5 per day with a free account. |
| Max file size, free | 500 MB |
Why convert MKV to MP4?
MKV (Matroska) is a powerful, flexible container, which is exactly why support for it is patchy: Safari and iOS will not play it, many TVs and phones choke on it, and a lot of editors and upload forms reject it. MP4 with H.264 is the universally accepted format. Converting trades MKV's flexibility for the one thing that matters when you want to actually watch or share the file: it plays.
What is MKV?
MKV is the Matroska container: an open, anything-goes wrapper that can hold any video codec along with unlimited audio tracks, subtitles and chapters. That flexibility makes it the favorite of screen recorders, rippers and archivists, and also the reason TVs, phones and editing tools reject it so often. Converting to MP4 trades the extras for a file that plays essentially everywhere.
What is MP4?
MP4 is the default container of modern video: phones record into it, cameras export it, and every browser, TV and editing tool plays it, usually carrying H.264 video and AAC audio. Being a container, an MP4 is really a box around separate video and audio tracks, which is why useful conversions include not just other video formats but also pulling the audio track out on its own.
Quality and what to expect
The primary video track is re-encoded to H.264 and the primary audio to AAC. This is a re-encode, not a lossless remux, so expect a small generational quality step at the high-quality default, in exchange for playing everywhere. One MKV-specific thing to know: MKV files often carry multiple audio tracks and subtitle tracks, and the conversion keeps the primary video and audio; extra audio tracks and embedded subtitles are not carried into the MP4. Dimensions are preserved (evened for H.264). On privacy, this is a server conversion: the upload is encrypted, the input is deleted immediately after conversion and the MP4 within about an hour, and the dropzone marks it a server conversion before you start.
MKV to MP4 FAQ
Why will not my MKV file play?
MKV is a container many consumer devices and browsers (notably Safari and iOS) never added support for, and it can hold codecs they do not decode. The file is usually fine; the player just cannot open that container. Converting to MP4 removes the problem.
Will my subtitles and extra audio tracks carry over?
No. The conversion keeps the primary video and audio and produces a clean MP4; embedded subtitle tracks and any additional audio tracks the MKV carries are not included. If you need a specific subtitle or audio track, that is worth knowing before you convert.
Will the video lose quality?
A small, usually imperceptible amount: the video is re-encoded to H.264 at a high-quality setting rather than copied bit for bit. The payoff is a file that actually plays on the devices that refused the MKV.
Is my video uploaded to a server?
Yes. Re-encoding a large video cannot run in a browser, so the MKV uploads over an encrypted connection, converts, and is deleted: the input immediately after conversion, the MP4 within about an hour. The dropzone labels it a server conversion before you start.