Convert MP4 files to MKV online, free and without signup. Upload your MP4 file below and download the converted MKV in seconds. You get 10 free conversions every day, and files are automatically deleted after 24 hours.
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PDF, DOCX, JPG, PNG, MP4, MP3, and 200+ formats
MP4 is the most widely supported video format playing on all devices.
MKV is an open-source container holding unlimited tracks.
Upload your MP4 file using the button above. Files up to your plan limit are supported.
Click Convert. Your file is processed on our servers with industry-standard engines like FFmpeg and LibreOffice.
Download your MKV file. It stays available for 24 hours, then it is deleted automatically.
Yes. ConvertFly offers 10 free conversions every day with no signup required. For higher volumes, credit packages start at $8.
Yes. Files are encrypted during transfer and automatically deleted after 24 hours. ConvertFly is operated by Dizzus GmbH in Switzerland.
No. The conversion runs entirely in the cloud: it works from any browser, on desktop or mobile.
| MP4 | MKV | |
|---|---|---|
| Type | video | video |
| In short | MP4 is the most widely supported video format playing on all devices. | MKV is an open-source container holding unlimited tracks. |
Convert MP4 to MKV online for free. Fast, secure video conversion powered by industry-standard engines. No signup required, files auto-delete after 24 hours. Operated by Dizzus GmbH on private infrastructure.