MKV to MP4 Converter
Export a Matroska video clip as an MP4 with H.264 video and optional AAC audio.
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MKV
Max file size: 100 MiB
A widely compatible MP4
The video is re-encoded to H.264 with AAC audio, the combination that phones, browsers, TVs, editing apps and social platforms accept. The file is arranged so that playback can begin before the download finishes.
Control size and quality
Limit the longer side to 480, 720, 1080, 1280 or 1920 pixels and choose Smaller file, Balanced or Higher quality. Video is never enlarged beyond its original size.
Trim and mute
Set a start time and a duration to export only the part you need, up to five minutes, and choose Mute to leave out the soundtrack.
How to convert MKV to MP4
- 1
Choose an MKV video up to 100 MiB.
- 2
Set the start time and clip duration in seconds, or leave the duration blank for a video of five minutes or less.
- 3
Choose the maximum dimension, the quality and whether to keep the audio.
- 4
Convert, then download the MP4 within about ten minutes.
What people use this tool for
- Make a screen recording saved as MKV playable in a browser, a chat app or a slide deck.
- Share a short clip from an MKV on a phone or platform that does not open Matroska files.
- Bring an MKV clip into a video editor that only imports MP4.
- Save a smaller, muted copy of a demonstration for a web page or a support ticket.
Frequently Asked Questions
How do I convert MKV to MP4?
Choose the .mkv file, set the start time and duration if you want only part of it, pick the maximum dimension and quality, and convert. Leave the duration blank to convert a video of five minutes or less from start to finish. Download the MP4 when it is ready.
Why re-encode instead of just changing the container?
MKV files often hold video in HEVC, VP9 or AV1 and audio in AC-3, DTS or Opus, which many phones, browsers and editors will not play from an MP4. Re-encoding to H.264 and AAC makes the result widely playable. The cost is a small loss of quality and a longer wait than a simple copy.
Which streams are included in the MP4?
The first video track and, unless you choose Mute, the first audio track, converted to stereo AAC. Subtitles, extra audio languages, chapters, attachments such as fonts, and metadata are left out, and subtitles are not burned into the picture. A video with no audio track converts normally.
Does the converter keep the original resolution?
It keeps it up to the maximum dimension you choose, which applies to the longer side. A 1920 × 1080 video stays that size at 1920 and becomes 1280 × 720 at the default 1280. Smaller videos are never enlarged. Dimensions are rounded down to even numbers, and frame rates above 30 fps are reduced to 30.
Can I convert a full movie or a long recording?
No. This tool is built for clips. The file can be up to 100 MiB and 30 minutes long, and each export is limited to five minutes and 80 MiB. At 1920 pixels a Full HD export is limited to roughly three minutes, and 4K sources to less. Lower the maximum dimension or shorten the clip if the export is refused.
Which quality setting should I use?
Balanced is a sensible default for sharing. Smaller file compresses harder and suits screen recordings, messaging apps and upload limits. Higher quality keeps more detail and produces a larger file. None of the settings is lossless, so keep the MKV if you need the original.
Why did my conversion fail or look washed out?
A conversion is refused when the file is incomplete, has no video track, is larger than 16 megapixels per frame or runs faster than 120 frames per second, and it stops if encoding takes longer than two minutes. HDR video is converted without tone mapping, so its colors can look flat or pale in the MP4.
Is my video uploaded, and when is it deleted?
Yes. Conversion runs on Zutilium's server, so the MKV is uploaded when you convert. After a successful conversion the upload is scheduled for deletion after about one minute and the result after about ten minutes. Cleanup runs once a minute, so removal is not instant. Download the MP4 promptly.