MP4 to MKV

Convert MP4 files to MKV for free. No size limit, no sign-up, nothing uploaded.

How to convert MP4 to MKV

  1. Choose your MP4 files or drop them on this page. You can add as many as you like.
  2. MKV is already selected. Press Convert, or Convert all for several files.
  3. Press Download. With several files you can download them all as one ZIP.

MP4 is the most widely supported video format, for phones, TV and the web. MKV is a video container often used for films with several audio tracks.

Questions

Is converting MP4 to MKV free?
Yes. ConvertBoy is free with no daily limit, no watermark and no sign-up.
Is there a file size limit?
No. Your own device does the work, so the only limit is your device's memory. Very large videos take longer on slower computers.
Are my files uploaded anywhere?
No. The conversion happens inside your browser. Your MP4 files never leave your device, and nothing is kept after you close the tab.
Does it work on a phone?
Yes. It works in Safari on iPhone and Chrome on Android, as well as on any computer.
How long does it take?
A song takes a few seconds. A video takes roughly as long as it plays on an average laptop, less on a fast one. The first time, the converter loads its video engine (about 30 MB).

Convert MP4 to another format

Convert other files to MKV