MKV to MP4 Converter
Convert MKV to MP4 without re-encoding. Matroska files with H.264 video and AAC sound – OBS recordings, for example – are remuxed into MP4 in seconds, entirely in your browser; other sound formats are converted to AAC so the MP4 plays everywhere.
- Free
- No upload
- No watermark
Files
Settings for all files
Options · Same quality · Original size · Sound on
More options
GIFs can be up to 60 s long (30 s on phones). Use Trim (⋯ on a file) to pick a part.
Same copies AAC sound without re-encoding when the file already has it.
16-bit PCM, the format CDs and every audio editor use.
Add files to see what will happen to each one.
Add files to convert
Runs in your browser. Engine: mp4box.js (BSD-3-Clause), mp4-muxer and webm-muxer (MIT), gifenc (MIT), LAME via lamejs (LGPL-3.0, GPL-3.0) – licenses.
What works in your browser
Everything runs on your device, so what you can create depends on the browser. The last column is checked live in the browser you are using now and always wins over the table.
| Output | Chrome / Edge | Chrome Android | Firefox 130+ | Safari 16.4–18 | Safari 26+ | This browser |
|---|---|---|---|---|---|---|
| MP4 (instant copy) | Yes | Yes | Yes | Yes | Yes | Yes |
| MP4 (re-encode, H.264) | Yes | Yes | Yes, sound as Opus | Yes, AAC sound copied only | Yes | – |
| MOV | Yes | Yes | Copies only | Yes, AAC sound copied only | Yes | – |
| WebM (VP9 + Opus) | Yes | Yes (slow) | Yes | Checked live | Checked live | – |
| GIF | Yes | Yes | Yes | Yes | Yes | – |
| MP3 | Yes | Yes | Yes | Yes, long files limited | Yes | – |
| M4A | Yes | Varies by device | Copies only | Copies only | Yes | – |
| WAV | Yes | Yes | Yes | Yes, long files limited | Yes | – |
| Opus | Yes | Yes | Yes | Copies only | Checked live | – |
Instant copies work in every browser. Without WebCodecs (older browsers) re-encoding is not available, but MP3 and WAV files can still be made.
How to convert MKV to MP4
- Choose one or more MKV files. Large recordings are fine: the file is read in pieces, never loaded whole.
- Keep MP4 selected. The plan shows "Instant copy" when video and sound can be copied, or which part is converted.
- Press Convert and watch the progress bar; copying a 1 GB recording usually takes well under a minute on a computer.
- Save the MP4 files one by one, or all together as a ZIP when you converted several.
Built for recordings
Its own Matroska reader
The MKV is parsed directly – including files without an index from interrupted recordings – instead of being played back in real time.
Correct timestamps
B-frame timing is recomputed for MP4, so the result plays smoothly and seeks accurately in every player.
Long files welcome
Memory use stays low because frames stream from the MKV into the MP4; the limit is your device's free memory, not an upload cap.
Frequently asked questions
Is MKV to MP4 free? Is the file uploaded?
It costs nothing and needs no account. The MKV is opened by your browser and the MP4 is written on your device, so even multi-gigabyte recordings never travel over the internet.
Does converting MKV to MP4 reduce quality?
When the MKV holds H.264 video – most OBS, HandBrake and camera MKV files do – the video is copied exactly, so there is no quality loss at all. Only sound that MP4 cannot hold is converted, and AAC at the chosen bitrate sounds like the original for normal listening.
What happens to subtitles and extra audio tracks?
This version keeps the main video and the default audio track. Subtitles, chapters, attachments and additional languages are left out, and the file row says so. Use a desktop tool such as MKVToolNix if you need to keep them.
How fast is MKV to MP4?
Copying is limited only by how fast your device reads the file – typically 150 MB per second on a laptop and around 40 MB per second on a phone. If the sound has to be converted, a short audio step runs before the copy.
Which browsers support MKV to MP4?
The copy works in all current browsers, because Zebra Convert reads MKV itself. Converting AC-3 sound needs a browser that can decode it; when it cannot, the file shows a "Convert without sound" button rather than failing halfway.
What happens to quality
MKV (Matroska) is a flexible container popular with OBS, screen recorders and video archives. The video inside is usually H.264, which MP4 can hold directly. Zebra Convert reads the MKV with its own demuxer, moves each video frame into the MP4 untouched and recalculates the decoding timestamps MP4 needs. The picture is identical and the conversion runs at disk speed.
Sound is copied when it is AAC. Dolby Digital (AC-3), FLAC, Vorbis or Opus sound is converted to AAC, which is small and plays on every device; if the browser cannot decode that sound, you can convert without sound instead. HEVC video in MKV becomes H.264 where possible. Subtitles, chapters and extra audio tracks are not carried over: the first video and the default sound track are used.