MKV to MP4 — Convert Online for Free
Convert MKV to MP4 right in your browser. The contents are usually H.264, so only the container changes — fast and without quality loss.
Drag and drop your file here or click to select
About the conversion
MKV (Matroska) is the container films and series are usually distributed in: it can hold several audio tracks and subtitle streams in one file. That very flexibility is why mainstream devices reject it — iPhones, most TVs and game consoles will not open MKV.
Inside an MKV there is most often the same H.264 with AAC audio that MP4 uses, so the conversion usually comes down to a container swap. When the codec inside already suits the target container, we only swap the container — the wrapper around the video track. That takes seconds even for large clips and, more importantly, leaves the picture untouched: quality stays exactly as it was. Re-encoding kicks in only when there is no way around it, and the tool tells you honestly which of the two paths was used.
The file is processed in your browser on your own device and is never uploaded — not to our server, not anywhere else. On the first run the browser downloads the engine once (~32 MB) and takes it from cache afterwards.
Frequently asked questions
How do I convert MKV to MP4 without losing quality?
Just add the file and run the conversion with MP4 as the target. If H.264 is inside, the track moves into the new container as-is — the picture is not re-compressed and the quality stays original.
What happens to multiple audio tracks?
The main track is carried over to the MP4. That is a limitation of the task itself: MKV is purpose-built for multiple tracks and subtitles, while MP4 is designed around a simple, widely compatible structure.
Are subtitles preserved?
Subtitles embedded in the MKV are not carried into the result. If you need them, save them as a separate file before converting — most players pick up external subtitles placed next to the video.
Why will my TV not play MKV?
Because manufacturers support a limited set of containers and MKV usually is not among them, even when the video inside is ordinary H.264. Swapping the container to MP4 settles it.
Does the file leave my device?
No. The conversion runs locally in the browser.