Convert MKV to MP4 Online
Convert MKV video to MP4 directly in your browser. Free, no signup, and your file is never uploaded.
Click to upload or drag a file here
Supported: MKV · Processed entirely in your browser
Converted entirely in your browser using a WebAssembly build of FFmpeg — your file is never uploaded anywhere. Larger files take longer and use more memory.
MKV to MP4 converts the less broadly-supported MKV container into MP4, which plays natively on far more devices, phones and browsers.
Why doesn't MKV play as widely as MP4, if it's technically such a capable format?
MKV was built to be maximally flexible — bundling multiple audio tracks, subtitle tracks and even multiple video streams into one file — but that flexibility never became the universal baseline that hardware makers, phone manufacturers and app developers built around, unlike MP4. The result is a format that's genuinely powerful for archiving and multi-language releases, but noticeably less reliable for simple everyday playback on a random phone or smart TV.
Will converting from MKV to MP4 lose any of the extra audio tracks or subtitles?
It can, depending on how many tracks the source MKV contains and how the conversion handles them — MP4 supports multiple tracks too, but MKV's ecosystem tends to be used specifically because it accommodates an unusually large number of them, so a conversion is worth checking afterward if the original file had several language or subtitle options bundled in.
Is this private, and does the video get uploaded anywhere?
No — conversion happens entirely in your browser, so the video is never uploaded to a server; it's also free, with no sign-up and no limit on how many files you convert.
Where did MKV's flexible, multi-track design actually come from?
The Matroska project began in Russia in 2002, led by developer Lasse Kärkkäinen and founder Steve Lhomme, building on an earlier open-container effort called MCF — the name itself is a playful nod to matryoshka, the Russian nesting dolls, since the format was built specifically to nest multiple video, audio, subtitle and image tracks inside one file. That same flexible container structure turned out to be valuable well beyond its original niche: when Google built WebM in 2010, it adopted Matroska's underlying container design wholesale rather than building a new one from scratch, meaning the open-source Russian project quietly became part of the technical foundation behind Google's own royalty-free video format too.
Is MKV to MP4 free to use?
Yes. MKV to MP4 is completely free, with no sign-up and no usage limits.
Do I need to install any software?
No. MKV to MP4 runs directly in your web browser — nothing to download or install.
Is my data kept private?
Everything happens on your device. We never receive or store the file or text you enter into MKV to MP4.