Updated June 2026 · runs 100% in your browser
MKV to MP4
Convert MKV videos to MP4 on your device. No upload, no sign-up, no limits.
Drop MKV files here
or click to choose
🔒 Processed on your device · 0 bytes uploaded
First file loads the converter engine (~25 MB) — cached after that.
How it works
ConvertCabin loads a local copy of FFmpeg in this browser tab and converts on your device — nothing is uploaded. The first file downloads the engine (~25 MB), then it's cached.
It stays free, unlimited and private, and works offline once loaded.
About MKV to MP4
MKV is flexible but not always supported; MP4 is the universal choice.
Frequently asked questions
How do I use MKV to MP4?
Drop MKV files and download the MP4s.
Is my file uploaded?
No. It is converted on your device by a local copy of FFmpeg and never uploaded.
What is an MKV file?
MKV (Matroska) is a flexible open video container that can hold multiple video, audio, and subtitle tracks in one file. It's popular for high-quality video but isn't supported by every player, so it's often converted to MP4.
What is an MP4 file?
MP4 is the most universally compatible video container. It typically holds H.264 video with AAC audio, plays on virtually every device, and balances good quality with reasonable file size.