Compress MKV Video Online
MKV (Matroska) is a flexible container often used for high-quality rips with multiple audio/subtitle tracks, which makes files large.
Drop your video here
or browse your files
Processed on your device — nothing is uploaded
Consolidates multi-track MKV files into a single, lightweight MP4 stream
Removes the overhead of unused audio/subtitle tracks you don't need
Produces a file that's playable in apps and platforms that don't support MKV natively
Why compress MKV files?
Compressing to MP4 strips down to a single video/audio track and re-encodes efficiently, drastically shrinking file size.
How it works
Step 1
Upload
Drop your file in — up to 500MB free.
Step 2
Pick a quality
Basic, Strong, or Superb compression.
Step 3
Download
Get your smaller video in seconds.
Frequently Asked Questions
MKV files often bundle multiple audio tracks (different languages), subtitle tracks, and chapter data alongside a high-bitrate video stream — all of that adds up in file size.
Yes, the compressor keeps one video and one audio track and outputs a standard MP4 — if you need a specific language track, make sure it's the default track in your source file.
Not natively in most cases — MKV support is inconsistent across devices and browsers, which is a common reason to compress and convert it to MP4.
It can, since MKV sources are often high-bitrate or 4K rips — larger source files simply take more processing time regardless of format.
'Basic' preserves the most detail for archival-quality sources; 'Strong' or 'Superb' are better if your goal is just a smaller file to share or stream elsewhere.