MKV to MP4
Make an MKV video play on phones, TVs, and browsers.
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or drag it here
An MKV or WebM file
- Takes
- MKV files holding H.264, HEVC, VP9, or AV1 video. ProRes and other editing codecs are read but cannot be rewrapped into MP4 — they are refused by name rather than half-converted.
- Size
- Any size. Nothing is rebuilt, so even huge files take seconds.
Your files stay on your device
How to use it
Drop an MKV here to turn it into an MP4 in seconds, with no quality lost — the video is repackaged, not rebuilt. Your file stays on your device.
MKV files often won’t play on iPhones, Safari, or smart TVs. The video inside is usually fine — it’s just in a box those devices don’t open. This moves it into an MP4 box, which plays almost everywhere.
Drop your MKV onto the box above. There are no settings, because nothing about the video changes: same quality, same size, same length. It takes seconds, even for big files.
Heads up: an MP4 holds one soundtrack and no subtitles, so extra languages and subtitles are left out (the first audio track is kept). The tool tells you before you start if any audio can’t come across.
Want a smaller file instead? Use Compress Video.
FAQ
Does it lose quality?
No. The video is copied exactly — nothing is rebuilt.
Why won’t my MKV play on my phone or TV?
Many devices can’t open MKV files, even though they can play the video inside. Converting to MP4 fixes that.
How long does it take?
Seconds for most files.
What happens to subtitles and extra languages?
They’re left out. The first audio track is kept.
Why was my MKV refused?
The video inside uses a type MP4 can’t hold. Use Compress Video to convert it.
How big an MKV can I convert?
Any size — even multi-gigabyte films.
How it worksFor the curious
MKV (Matroska) is a container that can hold the same H.264, HEVC, VP9, or AV1 video as MP4, plus multiple audio tracks, subtitles, and chapters. Safari, iOS, most TVs, and no browser play it natively.
The compressed packets are read out of Matroska and written into MP4 with no decoding or re-encoding, so the result is bit-for-bit the same video. Time depends on file size, not length or resolution, and memory use stays small because no frame is decoded.
An MKV can carry codecs an MP4 cannot. Unsupported audio (Vorbis, FLAC) is dropped with a warning; an unsupported video codec is refused by name and can only be converted by re-encoding with the compressor.