How to use the Compress MKV
- Choose the MKV.
- Choose a level or target size.
- Optionally reduce the resolution.
- Compress and download.
What is kept
The first video track and first audio track are kept and re-encoded (H.264 and AAC). Extra audio languages and subtitle tracks are not included in the compressed file; extract subtitles first if you need them.
OBS recordings
OBS recordings are often saved as MKV at high bitrates. Compressing a 1080p recording at "Recommended" typically cuts it to a third of the size.
Good to know
Compression uses H.264 (x264, "veryfast" preset) with either a quality target (CRF) or a calculated bitrate for target sizes. Audio is re-encoded to AAC. The file is never uploaded, so even private videos can be compressed safely.
Supported files
MP4, MOV, MKV, WEBM, AVI, WMV, FLV, M4V, 3GP, 3G2, MPEG, MPG, TS, MTS, M2TS, VOB, OGV, MXF, ASF, DIVX, F4V, SWF, DV, MOD, TOD, WTV, RM and RMVB video, with H.264, HEVC, VP8, VP9, MPEG-4, MPEG-2, WMV, Theora and other codecs. AV1 videos cannot be read in the browser yet. Files up to 1 GB each.
Frequently asked questions
Can I keep all audio languages?
Not with this tool; only the main track is kept.
Is the Compress MKV free?
Yes, completely free, with no sign-up and no watermark. Files up to 1 GB each can be converted, and there is no daily limit.
Do you keep a copy of my files?
We never receive them. All processing happens on your device, so there is nothing for us to store or delete.
Can I use it on my phone?
Yes. Open the page in your phone's browser and choose a file. Phones have less memory than computers, so very large files are better converted on a laptop or desktop.