Compress MKV Files Online

• MKV output in the full editor

  The compress tool outputs an H.264 MP4. If you need to keep MKV, the full editor on a paid plan exports to the MKV container with H.264, H.265, AV1, ProRes, or DNxHR inside, so nothing downstream in your player setup has to change.

• H.265 and AV1 for real savings

  H.264 is the safe default every device plays, and it is what the compress tool outputs. In the full editor on a paid plan you can switch to H.265, where a typical file lands near half the size at similar quality, or AV1, which squeezes tighter still. Older TVs favor H.264, archives favor the newer codecs.

• Resolution and quality you control

  In the compress tool, cap the resolution at 1080p, 720p or 480p and adjust the quality value until it looks right (a 4K source at 1080p carries a quarter of the pixels). A custom bitrate is in the full editor on a paid plan, whose export ladder runs from 480p up to 8K (Ultra).

• Trim the fat before you encode

  The cheapest compression is deleting footage nobody needs. Cut the dead air at the start of a recording with the video trimmer, or split the video and keep only the segment that matters, then compress what is left.

• Frame rate as a size lever

  A 60 fps screen recording carries twice the motion data of a 30 fps one, and most tutorials never needed 60. The compress tool's Advanced panel offers 24, 30, 60 or the original frame rate; other rates, up to 120 fps, are in the full editor on the Ultra plan.

• Cloud encoding, not your CPU

  Re-encoding an hour of MKV can pin a laptop's fans for ages in desktop tools. EchoWave renders on a cloud farm, so a Chromebook finishes the same export as a workstation. One honest trade: the file uploads first, so a huge source wants a decent connection.

• Or convert while you compress

  Need the file to play everywhere? Send it out as MP4 in the same pass with the MP4 converter, or browse the full video converter library, which covers 170+ conversion pages including MOV and WebM.

1. 1

   Upload your MKV

   Drag the file onto the compress tool or click to browse. MKV sits on the accepted input list alongside 19 other video formats, from AVI and WMV to M2TS and VOB. Browsers cannot always preview raw MKV, but the upload itself stays untouched and full quality.

2. 2

   Pick a level and read the estimate

   Choose Light, Balanced, Aggressive or Maximum. Each level shows an estimated size range, so you can see roughly what the file will shrink to before you start.

3. 3

   Set resolution, quality, and frame rate

   Open Advanced to cap the resolution at 1080p, 720p or 480p, adjust the quality value, and choose 24, 30, 60 or the original frame rate. The output is an H.264 MP4.

4. 4

   Compress and download

   The cloud render farm encodes at full quality no matter what device you are on, and you download the MP4. It is free, with no watermark, badge or end card. For MKV output, H.265 or AV1 or a set bitrate, use the full editor's export settings on a paid plan.

• Shrink OBS gameplay recordings

  OBS users often record to MKV because the format survives a crash mid-session. Those captures balloon at high bitrates, and re-encoding to H.265 makes an evening of gameplay practical to keep or share.

• Get under upload and attachment caps

  Chat apps and email providers reject multi-gigabyte files outright. Downscale and re-encode until the MKV fits, or trim out a short highlight instead of sending the whole session.

• Archive disc remuxes and camera dumps

  Remuxed Blu-rays with lossless audio can top 30 GB per film. Re-encoding to H.265 or AV1 keeps a copy that still looks good at a fraction of the size on your media server.

• Slim down lecture and course recordings

  Hour-long screen captures rarely need 60 fps or a lavish bitrate. Drop the frame rate to 30, step the bitrate down, and a semester of lectures fits on a single drive.

• Make MKV playable where it is not welcome

  Plenty of sites, phones, and TVs refuse MKV entirely. Convert to MP4 during compression and the same footage plays on every major platform without a second tool.

• Reclaim disk and NAS space

  Old project files and raw recordings quietly eat storage for years. Work through the backlog one file at a time and win the space back without deleting anything you might want later.

Based on each tool's public pages as of July 2026. HandBrake is free open-source desktop software, so it wins on offline use and batch queues, but it brings a learning curve and ties encode speed to your own CPU.