Free file converter
Convert MP4 to MKV online
Drop your MP4file below — we'll convert it to MKV instantly. No signup required.
Drop your file here
or click to browse — video, audio, images, documents, PDF
Up to 500 MB · No account required
Frequently asked questions
Are files uploaded to your servers?
No. Conversions run in your browser using WebAssembly and Canvas. Files stay on your device.
What is the max file size?
On the free tier, up to 250MB per file, plus up to 20 completed conversions per day on this device (limits help keep the service sustainable). Large video encodes can take time — keep the tab open while processing.
When should I use MKV?
MKV is a common choice when you need compatibility or a specific workflow. This page is built for MP4 → MKV.
Does it work offline?
After the app loads once, many conversions can continue without network access (depends on the browser).