MKV to MP4

MKV (Matroska) is an open, extremely flexible container that can hold practically any video and audio codec plus multiple audio tracks, subtitles and chapter markers at once - popular for anime fansubs, Blu-ray rips and archive collections. That very flexibility also makes MKV less compatible: many smart TVs, game consoles and older media players simply do not recognise the container, even though they could play the codec inside just fine.

If the MKV already carries H.264 or H.265 with AAC, AC3 or MP3 audio - the common case for most rips - the tool just repackages the file losslessly: every track (picture, every audio track, every subtitle track) is copied 1:1, nothing is recomputed. If the file instead carries VP9 or AV1 (e.g. from a web download), that does not fit MP4's lossless copy set - the tool then automatically re-encodes.

Honest note on subtitles: during a lossless repackage, embedded subtitle tracks are preserved, provided MP4 can hold that particular format. If a re-encode is needed instead, that path only processes picture and sound - subtitle tracks are lost in that case. Everything runs locally in the browser, with your video never uploaded.

Specifications

In 3 steps

1. Drop your MKV file.
2. The tool checks the codec and usually just repackages losslessly.
3. Download the MP4 file.

Limitations: If the MKV carries H.264/H.265 + AAC/AC3/MP3, the conversion is lossless and finishes in seconds, including every audio and subtitle track. With VP9/AV1, the tool automatically re-encodes - then only picture and sound are preserved, subtitles are lost. One file per run, ~1 GB limit (4 GB/tab in the browser).

FAQ

Related tools

MOV to MP4 · WebM to MP4 · MP4 to MKV · MP4 to WebM