Convert MP4 to MKV
Turn your MP4 file into an MKV that plays where you need it, right in your browser.
- Free to start
- In your browser
- Up to 500 MB
How to convert MP4 to MKV
Upload your MP4 file
Drag and drop a MP4 file, or click to browse. Up to 500 MB, and nothing is installed.
Confirm MKV as the output
MKV is already selected, so there is nothing to configure. Switch to another format in the panel if MP4 needs to go somewhere else.
Convert and download
We convert the MP4 on our servers, usually in under a minute. Create a free account to download the MKV, or keep editing it in REQO.
Why convert MP4 to MKV?
MP4 is the closest thing video has to a universal format: an MPEG-4 container that almost always holds H.264 video and AAC audio, which every browser, phone, TV and social platform can play without a plugin.
The practical problem: MP4 is already the safest format, so the usual reason to convert away from it is a specific destination that wants something else.
MKV solves that. Keeps multiple audio and subtitle tracks in one file.
Container
Typical codecs
Best for
Plays on
File size
| Feature | MP4 | MKV |
|---|---|---|
| Container | MPEG-4 Part 14 | Matroska |
| Typical codecs | H.264 video, AAC audio | Almost anything: H.264, HEVC, AV1, VP9 |
| Best for | Sharing anywhere, uploads, web embeds | Archiving with multiple audio and subtitle tracks |
| Plays on | Every phone, browser, TV and editor | VLC and desktop players; rarely anywhere else |
| File size | Small for the quality | Depends entirely on the codec inside |
MP4 to MKV questions
Is the MP4 to MKV converter free?
Yes. Convert and preview the result for free, then create a free account to download it. There is no per-file charge and no watermark on the MKV itself beyond the free-plan badge.
Do I need to install any software?
No. The conversion runs on our servers and the whole flow happens in your browser, so it works the same on Windows, macOS, Linux, iPhone and Android. Nothing to install at either end. Where MP4 plays: Every phone, browser, TV and editor. Where the MKV you get back plays: VLC and desktop players; rarely anywhere else.
Does converting MP4 to MKV reduce the quality?
Converting re-encodes the video, so it is not bit-for-bit identical. We encode at a high quality target, which keeps the result visually indistinguishable from the MP4 on normal viewing. What changes is the container and the codec. MKV holds: Almost anything: H.264, HEVC, AV1, VP9. Converting the same file back and forth repeatedly will eventually show, so keep your original.
How large a file can I convert?
Up to 500 MB per file, which is more footage in some formats than others. MP4: Small for the quality. MKV coming back: Depends entirely on the codec inside. For anything bigger, trim or compress it first, both are free tools here.
Is my file kept private?
Your upload is processed and then held only as long as your project needs it. Nothing is published, indexed or shared unless you create a share link yourself.
Other formats
Everything else you can do here.
Convert to MP4
Convert to WebM
Convert to MOV
Convert to AVI
Convert to MKV
Convert to WMV
Convert to MP3
Convert to M4A
Convert to AAC
Convert MP4 to MKV now
Free, in your browser, and the file stays open in a full video editor afterwards.