orbfile

MKV to MP4 Converter

Repack a Matroska file into the far more portable MP4. Drop a MKV file below — the whole conversion runs on your device.

Drop files, or click to browse

MKV files only — processed one at a time

Frequently asked questions

Is this MKV to MP4 converter free?+

Yes, with no watermark and no account. The engine runs locally in your browser, so there's no server queue limiting usage.

Is my video uploaded to a server?+

No. Orbfile uses your browser's own built-in media codecs (via the WebCodecs API and Mediabunny), so encoding happens entirely on your device.

How long will it take?+

It depends on your device and the video's length and resolution — expect roughly real-time to a few times real-time for typical clips.

Is there a maximum file size?+

There's no fixed upload limit — since everything runs on your device, the practical limit is your browser's available memory, which handles typical clips and even fairly long recordings without issue.

How do I convert MKV to MP4?+

Drop your MKV file into the box above — Orbfile re-encodes it to MP4 using your browser's own codecs and gives you a download link when it's done.

About MKV and MP4

What is MKV?

MKV (Matroska) is a flexible open container that can hold multiple audio tracks, subtitles, and chapters alongside the video.

Full MKV format guide →

What is MP4?

MP4 (usually carrying H.264 video) is the most widely compatible video container — it plays on essentially every phone, browser, and TV.

Full MP4 format guide →

MKV and MP4 solve different problems. MKV is great for archiving video with multiple language tracks or subtitles, but MP4 pulls ahead when you need maximum device and platform compatibility. If that's the situation you're in, converting is worth it.

How it works

  1. 1

    Drop your file in

    Drag your video onto the box above, or click it to browse — there's no account to create and no upload to wait on.

  2. 2

    Pick your settings

    The output format is already set for this page — just adjust any extra options shown, if there are any.

  3. 3

    Download the result

    Your browser processes everything locally and hands you a download link the moment it's done — nothing was ever sent to a server.

Is it private?

Everything happens locally, inside this browser tab. Your video is read from disk, processed with WebAssembly running on your own device, and handed back to you as a download — it's never transmitted anywhere, so there's nothing to intercept and nothing stored on a server.

Common use cases

  • Sharing
  • Uploading to social platforms
  • Uploading a clip to social media
  • Sending a video over email or chat

Supported formats

This is one of many pairings the video toolkit handles. In total it covers:

Related conversions

Format details

About MKV files+

MKV (Matroska) is a flexible open container that can hold multiple audio tracks, subtitles, and chapters alongside the video.

Matroska was designed from the ground up as an open, extensible container, meaning a single MKV file can bundle several audio tracks (say, multiple languages), several subtitle tracks, and chapter markers, all switchable during playback — something older containers like AVI and even MP4 handle less gracefully. That flexibility made it the format of choice for archiving TV shows and films with multiple language options, though a handful of phones and streaming devices still expect MP4 and need MKV converted first.

How to open a MKV file

Opens readily in VLC Media Player. For real editing, use DaVinci Resolve, Adobe Premiere Pro (with an extension).

Good for

  • supports multiple audio/subtitle tracks in one file
  • open format, no licensing fees

Watch out for

  • not natively supported by some phones and TVs without an app
Developed by: Matroska.orgReleased: 2002Wikipedia Full MKV format guide →
About MP4 files+

MP4 (usually carrying H.264 video) is the most widely compatible video container — it plays on essentially every phone, browser, and TV.

MP4 is a container format standardized under MPEG-4, meaning the file itself is really a wrapper that most often holds H.264-encoded video alongside AAC audio. That specific combination struck a balance efficient enough for streaming and broad enough to be adopted everywhere, which is why it's the format cameras, phones, editors, and social platforms converge on as a safe default. It isn't always the smallest or most efficient option available — newer codecs inside newer containers can do better — but nothing beats it for guaranteed playback.

How to open a MP4 file

Opens readily in Any web browser, Any modern phone, TV, or media player. For real editing, use Adobe Premiere Pro, DaVinci Resolve, iMovie.

Good for

  • maximum device and platform compatibility
  • good compression-to-quality ratio

Watch out for

  • not the smallest option available for the same visual quality
Developed by: MPEG (Moving Picture Experts Group)Released: 2001Wikipedia Full MP4 format guide →

Need a different format? Try the full Video Converter, or explore all video tools.