VidCompress / MKV compression
MKV files are often huge and not widely supported. Compress and convert to MP4 so the file fits and actually plays.
Or jump straight to a destination:
MKV is a flexible container often used for high-resolution video, which means MKV files are frequently huge — a single movie-length file can run several gigabytes. Many phones, browsers, and social platforms also refuse to play MKV. Compressing it shrinks the file and converts it to MP4 so it both fits and plays.
VidCompress reads your MKV, re-encodes it to a target size, and outputs an MP4. Files under 300 MB are processed locally in your browser, so nothing is uploaded.
Quick reference
Choose a target size
Use a destination preset (Email, Discord, WhatsApp, Telegram) or a custom MB target depending on where the file is going.
Drop in the MKV
Add your MKV file. VidCompress reads its resolution and length to plan the most efficient encode.
Compress and convert
The MKV is re-encoded to your target and converted to MP4 in the same pass.
Download the MP4
Save the result — smaller and playable on phones, browsers, and platforms that reject MKV.
How do I compress an MKV file?
Drop the MKV on this page and choose a target size. VidCompress re-encodes it smaller and converts it to MP4 in one step.
Does it convert MKV to MP4?
Yes. The output is MP4 (H.264), which plays on phones, browsers, and platforms that do not support MKV.
Why are MKV files so large?
MKV is often used for high-resolution, high-bitrate video, so files get big. Re-encoding to a target size in H.264 MP4 reduces them substantially.
Do I need to install anything?
No. MKV compression runs in your browser; files under 300 MB stay on your device.
Is it free?
Yes. The free plan compresses up to 300 MB locally with no signup or watermark.