TopTool
MP4→MKV

MP4 to MKV

MP4 to MKV is a free online video converter for changing MP4 files into MKV files. MP4 to MKV accepts 1 MIME type, returns video/x-matroska, includes 0 settings, and runs in your browser on the device.

Drop .mp4 file here

or click to choose

Key facts

Input
1 format: MP4 (video/mp4)
Output
MKV (video/x-matroska)
Runtime
your browser on the device
Settings
0 controls; default conversion path
File mode
1 input file creates 1 output file
Cost
$0, no account required

How to use MP4 to MKV

  1. 1

    Open your MP4 file

    Drop your MP4 file onto the page, or click to browse and pick one from your device.

  2. 2

    Choose options

    No options to configure. MP4 to MKV uses sensible defaults.

  3. 3

    Convert and download

    Click Convert. Your MKV file is ready to download in seconds.

MP4 to MKV details

First, MP4 to MKV reads MP4 source files and prepares MKV output for the video workflow. Next, MP4 to MKV keeps the conversion path simple with no extra controls. Additionally, Files and text stay in the browser session.

Repackage an MP4 file into an MKV container without re-encoding the video or audio streams. Because nothing is decoded; the existing streams are just copied into a new container; the conversion is very fast and there is no quality loss. MKV is a flexible open container that supports multiple audio tracks, subtitles, and chapters; it's popular for media libraries and home theater setups. The conversion runs locally in your browser via ffmpeg.wasm, so the file never leaves your device. For best results keep inputs under about 500 MB.

Common searches

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Related tools

Tools that work with the same formats — most users open one of these next.

VideoOnline

MKV to MP4

Convert MKV (Matroska) video to MP4 (H.264 + AAC) — free, runs in your browser.

MKV→MP4
VideoOnline

Video Trimmer

Cut a clip from a video file — MP4, WEBM, MKV, MOV, AVI — in your browser.

MP4→MP4
VideoOnline

Compress Video

Shrink a video file by re-encoding to H.264 with a quality preset — free, in-browser.

MP4→MP4
VideoOnline

MP4 to WebM

Convert MP4 video to WebM (VP9 + Opus) — free, runs entirely in your browser.

MP4→WEBM
VideoOnline

MP4 to MOV

Convert MP4 video to MOV (QuickTime) — free online, no upload.

MP4→MOV
VideoOnline

MP4 to GIF

Convert MP4 video to an animated GIF — free online, with a tuned palette.

MP4→GIF

Frequently asked

What is MP4 to MKV?

MP4 to MKV is a free online video converter for changing MP4 files into MKV files. MP4 to MKV accepts 1 MIME type, returns video/x-matroska, includes 0 settings, and runs in your browser on the device.

What files does MP4 to MKV accept and create?

MP4 to MKV accepts MP4 files (video/mp4) and creates MKV files (video/x-matroska). There are no required settings before conversion.

Do my files and data stay private?

Yes. MP4 to MKV runs entirely in your browser using your device's CPU. Files and text are never uploaded to our servers, so your data stays private.

How do I use MP4 to MKV?

Open MP4 to MKV, drop in your MP4 file, choose any options, and click Convert. Your browser does the work locally and produces a MKV file you can save right away.

What is the maximum file size for MP4 to MKV?

Because MP4 to MKV runs in your browser, the maximum size depends on your device's available memory. Most modern phones and laptops handle files up to a few hundred MB without issues.