MP4 to MKV Converter
Free Online MP4 to MKV Converter
Convert MP4 video files to Matroska (MKV) format instantly in your browser — no software to install, no registration, and no watermarks. Uploaded files are automatically deleted after one hour.
About MKV (Matroska)
MKV is a flexible, open-standard container format that can hold virtually unlimited video, audio, subtitle, and chapter tracks in a single file. It is the preferred format for media libraries, Plex/Kodi servers, and archival purposes. Unlike MP4, MKV supports soft subtitles (SRT, ASS), multiple audio tracks, and chapter markers natively.
Lossless conversion
This tool copies the video and audio streams directly from the MP4 container into MKV without re-encoding. The result is zero quality loss and near-instant processing. The output file will be approximately the same size as the input.
Frequently asked questions
Is there any quality loss?
No. The streams are remuxed (repackaged) without re-encoding, so every pixel remains identical to the original MP4.
Can I play MKV files on my phone?
Most Android devices play MKV natively. On iPhone, use a third-party player like VLC. MKV is not supported in web browsers, so for web use, stick with MP4 or WebM.
Similar conversions: MP4 to WebM, MP4 to MOV, MKV to MP4.