MKV to MP4 Converter

Convert MKV video to MP4 so it plays on devices that refuse the format. Usually a straight copy — seconds, and no quality loss.

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  • No watermark
  • Unlimited files
Drop a MKV file hereor tap to browse · one file at a time · nothing is uploaded

    On the default setting this usually finishes in seconds, because the picture and sound are copied across unchanged rather than re-encoded. Everything runs on your own device — the file is never uploaded.

    MKV is a container, not a video format

    Matroska — MKV — is a flexible open container. It can hold almost anything: several video tracks, a dozen audio languages, subtitles, chapters. That flexibility is exactly why hardware often refuses it, and why a great many TVs, phones and consoles will not play an MKV at all.

    The video inside is usually H.264 or HEVC, both of which are perfectly valid in an MP4. When that is the case the conversion is a repackaging job: the streams are copied into the new container unchanged, in seconds, with no loss.

    What can get left behind

    MP4 is stricter than MKV, so some things do not survive. Subtitle tracks in MKV are often stored in formats MP4 does not support, and extra audio tracks or chapter markers may be dropped.

    If a file has subtitles you need, keep the MKV as well. The MP4 is for playing on a device that will not read Matroska, not a full replacement for it.

    When re-encoding is unavoidable

    Some MKV files use codecs MP4 cannot hold. VP9 and AV1 video are increasingly common in downloads, and neither is standard in an MP4. Older files sometimes use Vorbis or FLAC audio, which likewise does not belong there.

    The tool tries copying first and falls back to re-encoding only when it must. Re-encoding takes minutes rather than seconds and costs some quality, and the finished file tells you which happened.

    Frequently asked questions

    Are my files uploaded to a server?

    No. The conversion runs inside your browser using your device's own processor. Your files are never transmitted anywhere, which is why the tool works even if you disconnect from the internet after the page loads.

    Why is it so much faster than other converters?

    Because in most cases it does not re-encode anything. The two formats commonly hold identical video and audio, so the streams are copied into the new container as they are. Sites that upload your file re-encode everything by default, which is slower and loses quality.

    Will my subtitles carry over?

    Often not. MKV usually stores subtitles in formats MP4 does not accept, so they may be dropped. Keep the original MKV if the subtitles matter.

    What about multiple audio tracks?

    The main track is kept. Additional language tracks may not survive, because MP4 handles multiple audio streams less gracefully than MKV does.

    Why did mine take several minutes?

    The video was almost certainly VP9 or AV1, neither of which fits in an MP4, so it had to be re-encoded. That is genuine processing work rather than a repackaging job.

    Is there a file limit or a paywall?

    There is no account, no watermark, and no upload cap. Because your device does the work, the only practical limit is your available memory. The site is funded by ads, not subscriptions.

    Further reading

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