MKV to MP4 Converter
Convert MKV files into MP4 that plays on any device. Free and private, right in your browser.
Why convert MKV to MP4?
MKV (Matroska) is a flexible container popular for recordings and downloads, but many phones, TVs, video editors and web browsers cannot play it. Converting to MP4 with H.264 video and AAC audio gives you a file that works practically everywhere.
Smushify re-encodes the video, which also lets you shrink it by choosing a lower quality or width.
How to convert MKV to MP4
Drop your MKV files above, keep MP4 selected, choose a quality and maximum width, and click Convert All. Because the video is re-encoded on your device, long files take time; keep the tab open until it finishes. Output is capped at 1920 pixels wide.
Frequently asked questions
Why won't my MKV file play?
Many devices and browsers do not support the MKV container. MP4 is supported almost universally, so converting usually solves playback problems.
Why does conversion take a while?
Smushify fully re-encodes the video on your own device instead of uploading it to a server. Speed depends on the video length and your computer.
Are my files uploaded anywhere?
No. Smushify converts everything inside your browser using WebAssembly. Your files are never sent to a server, so it is safe for private photos, client work and unreleased videos.
Can I convert many files at once?
Yes. Drop in as many files as you like, use "Format for all" and "Quality for all" to set every file in one go, then click Convert All and Download All.
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