Compress MKV
Drop an MKV and get a much smaller MP4, at the quality and resolution you pick.
Your file stays on your device. Nothing is uploaded.
Compress MKV in three steps
Drop your MKV
Up to 500 MB.
Pick quality and resolution
Balanced at 720p is a good start.
Compress and download
You get an MP4 that's a fraction of the size.
Why the result is an MP4
MKV (Matroska) is a flexible container that can hold several audio and subtitle tracks. OBS and other recorders use it because a recording survives a crash, but phones and many editors don't open it.
Compressing means re-encoding, so the tool saves the result as an H.264 MP4: it compresses well and plays everywhere, including the apps that won't open an MKV. Sound is saved as 128 kbps AAC.
Resolution makes the biggest difference: going from 1080p to 720p cuts the pixels by more than half, and on a phone screen it looks the same. Then pick Balanced, or Smallest file for hard limits like email.
Frequently
Asked Questions
Why do I get an MP4 back?
MP4 compresses well and plays everywhere, so it's the most useful result.
How much smaller will it get?
Often 70 to 90 percent smaller at 720p Balanced, depending on the source.
Is my file uploaded?
No. It's processed in your browser, on your own device, and never leaves it.