LocalConvert
Video Converter

Convert video to MKV — free & private

Convert MP4, WEBM, AVI, MOV and more to MKV container format. Runs entirely in your browser.

No server uploads100% privateGPU acceleratedOpen source

How to convert to MKV

  1. 1

    Choose your file

    Click or drag any MP4, WEBM, AVI file onto the uploader above.

  2. 2

    Pick MKV format

    Select MKV from the format dropdown in the converter.

  3. 3

    Save

    Hit the convert button, then save your MKV file to your device instantly.

Supported input formats

.MP4.WEBM.AVI.MOV.FLV

FAQ

Is the MKV converter really free?

Yes, completely free. No hidden fees, no watermarks, no file size limits. LocalConvert is open source and free forever.

Are my files safe?

Absolutely. Your files never leave your browser. All conversion happens using WebAssembly running locally on your device — no uploads, ever.

What files can I convert to MKV?

You can convert MP4, WEBM, AVI, MOV, FLV files to MKV.