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Convert MKV to MP4

Turn MKV videos into MP4 files that play on phones, TVs and in browsers. The video is copied into the MP4 instead of re-encoded, so quality stays exactly the same and it takes seconds. It runs in your browser, so your videos are never uploaded.

Drop MKV videos hereChoose MKV videos

They become MP4 files right on your device.

Your files stay on this device. Nothing is uploaded.

How to convert MKV to MP4

  1. Add your MKV videos

    Drop one or more MKV files on the blue box on this page, or choose them from your device.

  2. Wait a few seconds

    Each video is rewrapped into MP4 on your device. Even large files take seconds, because the picture is copied rather than re-encoded.

  3. Download the MP4

    Play the result on the page, then download it. Each file's row says what was copied, what was converted and where it plays.

MKV to MP4: details

Input
MKV (Matroska)
Output
.mp4 with the original video stream
Quality
Unchanged; the video is copied, not re-encoded
Video
H.264, H.265, AV1 and VP9 are copied as they are; VP8, MPEG-2 and older codecs need re-encoding
Audio
Kept as it is when an MP4 can hold it (AAC, MP3, Opus, FLAC, AC-3, E-AC-3); DTS, Vorbis, PCM and others become AAC. Convert to AAC makes sound that plays everywhere
Tracks
The main video and the default audio track; subtitles and extra audio tracks are left out
Metadata
The recording date is kept; the location (GPS) is left out
Upload
None; videos are converted in your browser
Several files
Yes, add as many as you like
Price
Free

MKV to MP4: questions

How do I convert MKV to MP4?

Rewrap the video instead of re-encoding it. On tuul.io you add your MKV files and download the MP4s: the video is copied over as it is, so quality stays the same and even a large file takes seconds rather than minutes.

Does converting MKV to MP4 lose quality?

The video doesn't: it's copied as it is. By default the sound is kept as it is too when an MP4 can hold it (AAC, MP3, Opus, FLAC, AC-3 and E-AC-3); DTS, Vorbis and PCM are converted to AAC. Choose Convert to AAC for a file whose sound plays everywhere.

What happens to subtitles and extra audio tracks?

The MP4 gets the main video and the audio track marked as the default (usually the main language or the 5.1 mix), or the first one when none is marked. Subtitles and other audio tracks are left out, and the file's row says so.

Which MKV files can't be converted?

Files whose video is VP8 or an older codec such as MPEG-2. An MP4 can't hold VP8, and it can hold MPEG-2, but phones and browsers can't play it from an MP4. The row names the codec when that happens. Those files need re-encoding, for example with HandBrake.

Are my videos uploaded?

No. The converter downloads once to your browser and then runs on your device, so your videos never leave it.

Can I convert several videos at once?

Yes. Add as many as you like; they are converted one after another and each gets its own download button.

Does it work on a phone?

Yes, in current versions of Safari and Chrome. Very large files can run out of memory on phones, so for videos over about 1 GB a computer is more reliable.

Next steps

  • Video trimmerCut the part you need out of a video or CCTV recording, without re-encoding it.
  • Video to MP3Take the sound out of any video, CCTV too, as MP3.

More video tools

  • MOV to MP4Rewrap MOV videos as MP4 without losing quality.
  • AVI to MP4Rewrap AVI videos as MP4 without losing quality.
  • TS to MP4Rewrap TS videos as MP4 without losing quality.
  • WebM to MP4Rewrap WebM videos as MP4 without losing quality.