MKV to MP4 Converter — Free, No Upload
Convert MKV to MP4 — usually instantly, and without quality loss.
Drop a file here
or click to choose a file
Runs on your device Your file is processed by your own browser and is never uploaded to a server.
Short answer
MKV files can be converted to MP4 in a browser, and in most cases without re-encoding. MKV usually already contains H.264 video and AAC audio, so the streams can be copied straight into an MP4 container — a remux that takes seconds and loses no quality. Re-encoding is only necessary when the file uses a codec MP4 does not support.
At a glance
| Accepts | MKV (Matroska) |
|---|---|
| Produces | MP4 (remux or H.264 / AAC) |
| Processing | In your browser |
| Price | Free, no limits |
| Account | Not required |
MKV, or Matroska, is a flexible open container widely used for high quality video, but support outside desktop players is patchy. The important thing to understand is that MKV and MP4 are wrappers, not codecs — the video inside is usually identical H.264.
That is why Remux is the default here. It rewrites the wrapper and leaves the video and audio data untouched, so it is instant and mathematically lossless. Switch to Re-encode only if remuxing produces a file that will not play.
How to use it
- 1
Add the MKV file
Drop in the .mkv file you want to convert.
- 2
Choose remux or re-encode
Remux is instant and lossless. Re-encode is slower but handles unusual codecs.
- 3
Convert
The container is rewritten, or the streams are re-encoded, on your device.
- 4
Download the MP4
Save the result.
Frequently asked questions
What does remuxing mean?
Remuxing rewrites the container around the existing video and audio data without decoding or re-encoding it. It is fast and completely lossless because the media streams are copied unchanged.
Remuxing produced a file that will not play. What now?
The MKV probably contains a codec MP4 does not support, such as VP9 video or FLAC audio. Switch to the Re-encode option.
Are subtitles carried over?
Embedded MKV subtitle tracks are generally not transferred. Extract them separately if you need them.
Does MKV have better quality than MP4?
No. Container format does not determine quality — the codec and bitrate inside do. An MKV and an MP4 holding the same H.264 stream are visually identical.