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First run downloads FFmpeg (~25 MB) once in this browser. Need audio only? Try /mkv-to-mp3.

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MKV to MP4 converter online free

Convert MKV to MP4 online free. Free MKV to MP4 converter — turn Matroska (.mkv) into H.264 MP4 with adjustable quality, no server upload.

What is an MKV to MP4 converter?

An MKV to MP4 converter (also searched as Matroska to MP4 or MKV to MP4 format converter) changes Matroska (.mkv) video into widely supported MP4, usually H.264 video and AAC audio. Use it to convert MKV to MP4, convert .mkv to .mp4, or change an MKV file to MP4 for phones, browsers, and social apps. This free tool runs locally with FFmpeg WebAssembly — no server upload.

MKV to MP4 converter features

Free online MKV to MP4 video converter — browser-based Matroska to MP4.

  • Convert MKV to MP4 online

    Upload a .mkv file and download a compatible MP4 in your browser.

  • Matroska to MP4

    Re-encode Matroska containers into web-ready H.264 MP4.

  • MKV to MP4 format converter

    Change MKV format to MP4 for players and devices that prefer MP4.

  • Adjustable output quality

    Tune H.264 CRF to balance visual quality and MP4 file size.

  • No server upload

    FFmpeg WebAssembly processes video on your device for better privacy.

  • Web-ready MP4

    Output uses even dimensions, H.264, optional AAC, and faststart.

How to convert MKV to MP4

How to change MKV to MP4 or convert .mkv to .mp4 online.

  1. Upload MKV file

    Drop or select your .mkv video (up to 200 MB).

  2. Set quality (CRF)

    Keep the default CRF 23 for balanced quality, or lower CRF for sharper output.

  3. Convert and download

    Click Convert to MP4, then download the result.

Great for

Common MKV to MP4 and Matroska to MP4 scenarios.

  • Anime and TV rips

    Convert MKV episodes to MP4 for phones and streaming boxes.

  • Cross-device playback

    Turn Matroska files into MP4 for wider player support.

  • Editing and uploads

    Standardize MKV footage to MP4 before posting or editing.

  • Sharing by chat or email

    Create MP4 files recipients can open without MKV codecs.

Frequently Asked Questions

Quick answers about this tool—open a question to read more.