MKV → MP4
MKV to MP4 Converter
Drop a file here
Click to browse, or paste a file from the clipboard.
Choose fileAn MKV to MP4 converter copies the video and audio already inside a Matroska file into an MP4 wrapper phones and sites accept. Videozify remuxes the file. When the codecs already fit MP4, picture quality does not change — only the container does.
How to convert MKV to MP4
- Drop your MKV file onto the box above, or click Browse to choose it from disk.
- Confirm the selected title is the one you want; this path copies streams without re-encoding.
- Press Convert and wait until the progress bar reaches one hundred percent.
- Download the MP4 when it appears; the file saves only to this device.
Why convert MKV to MP4?
MKV is a Matroska container that can hold almost any codec, several audio tracks, and subtitle streams in one file. That flexibility is why rips, anime batches, OBS recordings, and some YouTube downloads land as MKV. iPhone, Safari, Twitter/X uploads, and a lot of school portals still want MP4. You are swapping the box, not inventing a new encode, when the video is already H.264 or HEVC and the audio is already AAC.
People reach for this page after a file plays in VLC and nowhere else. VLC is a polyglot. The phone in your pocket is not. Remuxing is the smallest change that satisfies picky players. File size stays nearly identical because the frames are copied. If someone promised you a 90% shrink, they described a compressor, not a container swap.
This preset uses stream copy and fast-start. Quality is unchanged when the copy succeeds. It can fail when the MKV holds codecs MP4 will not store, or when subtitle and attachment tracks confuse the remux. Those extra tracks are often dropped or they abort the job. If you need burned-in subtitles, that is a different, lossy process this page does not pretend to do.
Use this for Plex libraries you want to AirDrop, for class uploads that whitelist .mp4, and for recordings that are already H.264 inside Matroska. If the MKV is VP9 or a rare video codec, remux may error; that file needs a re-encode instead of this tool.
If the MP4 is still too large to send, compress the video as a second step. If you only needed a scene, trim the video instead of remuxing a two-hour file for a one-minute clip.
MKV vs MP4: what's the difference?
| MKV | MP4 | |
|---|---|---|
| Extension | .mkv | .mp4 |
| Type | Matroska container | MPEG-4 container |
| Typical size (4 min) | 40–80 MB | Almost the same (remux) |
| Compression | Whatever codec is inside | Same codecs, new wrapper |
| Quality | Source streams | Unchanged if streams copy |
| Device support | VLC, desktop players | Phones, Safari, most uploaders |
MKV is a Matroska container that can hold almost any video codec, extra audio tracks, and subtitles in a single file.
Does converting MKV to MP4 reduce quality?
No, on a successful remux. The preset copies the bitstreams. There is no CRF, no bitrate slider, and no second generation of H.264. If the output looks softer, you did not use this tool — or the source was already soft.
The MP4 will not magically gain iPhone playback if the video codec is something iPhone cannot decode. HEVC in MKV becomes HEVC in MP4. H.264 in MKV becomes H.264 in MP4. The wrapper change only helps when the destination's problem was Matroska, not the codec.
Output size should hug the input size. A large drop means streams were left out (audio missing, attachments dropped) or the job was not a copy. Open the MP4 and check that picture and sound both survived before you delete the MKV.
What happens to subtitles in the MKV?
Soft subtitle tracks inside MKV are the feature Matroska is famous for and MP4 is awkward about. This remux copies video and audio. Subtitle tracks are not guaranteed to survive, and some of them cause the copy to fail. If the job errors, try a copy of the MKV with subtitles stripped in a desktop muxer first.
Hardcoded (burned-in) subtitles are part of the video picture. They remux with the video and still show. That is why fansub files that already burned the signs look fine after an MP4 wrap, while a PGS or ASS track may not.
Chapters, fonts, and cover attachments are Matroska extras. Do not expect them in the MP4. If those matter, keep the MKV as the archival file and treat the MP4 as the portable playback copy.
Frequently asked questions
Does converting MKV to MP4 reduce quality?
- Not when stream copy works. The pixels are not re-encoded. Quality stays the same as the MKV. If the MKV used a codec MP4 cannot hold, the job fails instead of secretly crushing the picture. Keep the MKV until you have played the MP4 on the target device.
Why does the file play in VLC but not on iPhone?
- VLC decodes Matroska and a long list of codecs. iPhone wants MP4, usually with H.264 or HEVC and AAC. Remuxing fixes the container. It does not add an H.264 encode if the MKV was VP9 or something else. In that case you need a re-encode, not this page.
Will my subtitles still be there?
- Burned-in subtitles stay, because they are in the picture. Soft tracks often do not copy cleanly into MP4 and can even make remux fail. If dialogue subtitles matter, confirm them in the MP4 before deleting the MKV, or burn them in an editor first.
Will this work on iPhone or Android?
- The converter runs in mobile Safari and Chrome. Large MKVs still have to load into memory, so a multi-gig rip can kill a phone tab. Convert big files on a computer.
Can I convert several MKV files at once?
- Not in this version. One remux at a time keeps RAM stable. Convert, download, then drop the next file. After the engine loads once, later remuxes skip that wait. A folder of episodes is still one Matroska file per drop.
Is it legal to convert MKV to MP4?
- Repackaging a recording you made, or a file you have permission to use, is normally fine. Changing the wrapper on a commercial title you do not have rights to does not create a licence. Videozify does not store files and cannot check your rights.