Convert MP4 to MKV
MP4 is great for sharing video anywhere — phones, social media, web and TVs, but MKV is the better choice for movies with multiple audio tracks and subtitles. Convert MP4 to MKV in seconds, right in your browser.
- No upload — 100% private
- Fast, lossless when possible
- Free & unlimited
- Works on iPhone & Android
Keep this tab open — the conversion runs on your device, nothing is uploaded.
Add more files above to keep converting.
How to convert MP4 to MKV
- 1
Tap Choose files and select one or more MP4 files (or drag them in).
- 2
Check that MKV is selected. Use Advanced options for resolution, size or trimming.
- 3
Press Convert. Everything happens on your device — no upload, no waiting in a queue.
- 4
Your MKV downloads automatically. Converting several files? Grab them all as a ZIP.
MP4 vs MKV
MP4 and MKV can hold the same codecs, so in Smart mode the streams are copied — the conversion takes seconds and quality is identical to the original.
| MP4 | MKV | |
|---|---|---|
| Full name | MPEG-4 Part 14 | Matroska Video |
| Type | Video | Video |
| Compression | Lossy | Lossy |
| Developed by | MPEG | Matroska.org |
| Introduced | 2001 | 2002 |
| Plays on iPhone | ✓ Yes | ✕ No |
| Plays on Android | ✓ Yes | ◐ Partly / with an app |
| Plays on Windows | ✓ Yes | ✓ Yes |
| Plays on Mac | ✓ Yes | ◐ Partly / with an app |
About MP4 and MKV
MP4: MP4 is the universal video format. With H.264 video and AAC audio it plays on every iPhone, Android phone, smart TV, browser, WhatsApp, Instagram and YouTube.
MKV: MKV is a flexible open container that can hold unlimited video, audio and subtitle tracks. It is popular for movies and anime but isn't supported by iPhone or most TVs out of the box.
Frequently asked questions
How do I convert MP4 to MKV on my phone?
Will converting MP4 to MKV reduce quality?
Is this MP4 to MKV converter free?
Are my files uploaded to a server?
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