Convert an MKV (Matroska) video to MP4 so it plays on phones, TVs, and every video editor — free, in your browser.
MKV is a fantastic archival container — it can hold almost any codec and any number of audio tracks or subtitles — but that flexibility is exactly why it's the worst guest at most video parties. iOS and many smart TVs refuse to play it; older editing software either rejects it outright or drops tracks silently. MP4 is the safe common denominator.
When the MKV's video and audio codecs are already MP4-compatible (H.264 / H.265 / AAC), we remux: we pop the streams out of the Matroska container and drop them into an MP4 shell untouched. That's lossless and takes seconds. If the codecs aren't compatible, we re-encode with your browser's hardware encoder — still local, still free, no upload.
MKV (Matroska) is a flexible open-source container often used for high-quality releases. It can pack almost any codec, which is why MKVs sometimes fail to play on devices that only understand MP4.
MP4 is the most widely supported video container. Output here is mastered with fast-start so it plays instantly in web and mobile players.
Drag a MKV onto the converter above, or click the box to pick one from your device.
We've preselected MP4 as the output format. Change it from the dropdown if you want a different target.
Click Convert and wait for the progress bar to finish. Download the MP4 when it's ready.
Pull the audio out of an MKV video file and save it as an MP3 — local, free, no signup.
Turn a QuickTime MOV (from your iPhone or Mac) into an MP4 that plays everywhere — in seconds, in your browser.
Convert a WebM video (downloaded from YouTube, Twitter, or a web recorder) to MP4 — fast, in your browser, no upload.