About this MKV to MP4 tool
MKV (Matroska) is a flexible container that many players don't support. When the video inside is H.264 or HEVC, the tool simply moves it into MP4, which is fast and lossless.
If the MKV contains VP9 or another codec, the video is re-encoded to H.264 automatically. Only the main video and audio tracks are kept; subtitles are not carried over.
How to use MKV to MP4
- Choose or drop the MKV file.
- Click Convert video.
- Download the MP4.
Features
Fast copy
No re-encode for H.264 and HEVC.
Auto re-encode
Other codecs become H.264.
Private
Nothing is uploaded.
Good to know
- Works in up-to-date Chrome, Edge, Firefox and Safari on computers and Android. iPhones with iOS 17 or newer work too.
- Files up to about 1 GB work well on most computers. Phones handle shorter clips best.
- Only edit videos you own or have permission to use.
Frequently asked questions
Are subtitles kept?
No. Only the main video and audio tracks are converted.
Which audio is used if the MKV has several languages?
The default (first) audio track.
Is there a size limit?
No fixed limit; files up to about 1–2 GB work on most computers.
Is my video uploaded?
No. The whole job runs inside your browser using your device's built-in video encoder, so the video never leaves your device.