Video conversion
Convert MKV to MP4
Updated Jul 2026
MKV is a flexible container that can hold multiple audio tracks, subtitles, and almost any video codec, but a lot of phones, smart TVs, and apps won't open it. MP4 is the format nearly everything plays. To convert MKV to MP4, open the file in a converter and export it as MP4, right on your own computer, with nothing uploaded anywhere.
- Extension
- .mkv
- Type
- Video
- Typically
- High-quality video containers
- Extension
- .mp4
- Type
- Video
- Typically
- The universal video format
- Compression
- Lossy
Convert MKV to MP4 on your own computer. Nothing uploads.
How to convert MKV to MP4
- Open Morphjet and drag in the MKV file, or a whole folder of them, to convert several at once.
- Choose MP4 as the output format.
- Convert. The MP4 is written next to your original, and the file never leaves your computer.
MKV vs MP4: what actually changes
| MKV | MP4 | |
|---|---|---|
| Opens everywhere | No, needs a compatible media player | Yes, plays on phones, browsers, and TVs |
| File size | Similar or larger, since it's just a container | Often smaller after re-encoding, or unchanged if only repackaged |
| Quality | Lossless container, holds whatever the source codec captured | Very good, with a small loss only if the codec has to change |
| Multiple audio tracks and subtitles | Yes, can hold several of each | Limited, usually one audio track and basic subtitle support |
| Chapters and metadata | Full support | Basic support |
| Uploading and streaming | Rejected by most sites and apps | Accepted almost everywhere, including social media and cloud storage |
When to convert, and when not to
Convert MKV to MP4 when you want to watch a file on your phone, in a browser, or on a smart TV, or when a site or app only accepts MP4 uploads.
Keep the MKV if you rely on its multiple audio tracks, subtitle options, or chapter markers, since MP4 usually keeps only one of each.
Why not just use an online converter?
MKV files are often movies, recordings, or home videos you'd rather not hand over to a stranger's server. Uploading one to an online converter means a large, personal file sits somewhere out of your control while it processes. Converting on your own computer keeps the video, and everything in it, on your machine the whole time.
Questions
Does converting MKV to MP4 lose quality?
It depends on how it's done. If the video inside is just repackaged into MP4, quality stays the same. If the codec has to change, there's a small, one-time re-encoding loss.
Will I lose subtitles or extra audio tracks?
MP4 doesn't handle multiple audio tracks and soft subtitles as well as MKV does, so depending on the tool you may end up with only one audio track, or subtitles burned into the picture.
Why won't my MKV file play on my phone or TV?
MKV is a flexible container built mainly for desktop media players, and a lot of phones, smart TVs, and streaming apps only recognize MP4. Converting fixes that.
Can I convert a whole folder of MKV files at once?
Yes. Morphjet can take a folder of MKV files and convert all of them to MP4 in one pass.
Can I convert MKV to MP4 without uploading it anywhere?
Yes. A desktop app like Morphjet converts the file locally, so a large video never has to travel over the internet or sit on someone else's server.
Morphjet converts MKV, MP4, and 1,800+ other formats, all on your machine. Launching this July.