Turn a supported MKV into a shareable MP4 on your device. This tool keeps the primary video and audio, not extra soundtracks, subtitles or attachments.
Drop a video here
MKV / Matroska · Up to 2 GB on a computer
Converting video…
Runs on your device. Keep this tab open.
ChatCut opens in a new tab with your request. Add your file there.
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Why ChatCut
Get H.264 video with AAC audio when the source has a supported audio track.
H.264 and AAC tracks can move from MKV to MP4 without re-encoding.
Use the primary audio track for a simple review copy. Keep the MKV for alternate languages.
Embedded subtitle tracks and font attachments are not included in the output.
The MKV is read and processed in your browser tab.
Preview the MP4 and check its size before saving a separate copy.
How it works
Pick a supported MKV file from your device. Keep it within 128 MB and 5 minutes.
Start the local conversion to MP4. Keep this tab open until the file is ready.
Check the result, save the converted copy, or restart with another video.
Learn
MKV uses the Matroska container, which can hold video, multiple audio tracks, subtitles and attachments. A recording or archive may therefore include more than the picture and sound you hear by default. MP4 is another container, and this page writes a specific H.264/AAC version of it. The purpose here is a straightforward playback copy. It is not a way to preserve every element of a multi-track source in a new package.
The engine selects the primary video and primary audio from the file. H.264 video and AAC audio can be copied without encoding those tracks again. If either selected track uses another supported codec, that track is re-encoded to the output codec instead. The decision is made separately for picture and sound. There is no soundtrack selector on this page, so check the language in the preview before using the MP4 for a review or handoff.
Embedded subtitle tracks, additional audio and attached files are left out of the result. Text already burned into the video image remains part of the picture, but a separate selectable subtitle track is not burned in by this converter. Keep the original MKV if you need alternate languages or attached fonts later. If the review copy needs captions, add them in an editing workflow afterward and verify their placement against the converted video.
The 128 MB and five-minute caps are only the first checks. A file also needs readable video data, valid dimensions and codecs that the browser can handle. Unsupported primary audio stops the conversion instead of producing an unexpectedly silent clip. Changing only the container does not make unsupported compressed data readable. When necessary, use a desktop converter to prepare H.264/AAC first. Compare the output size too, because a conversion is not an automatic compression pass.
Use cases
Make a short MP4 copy for a player or service that does not accept MKV.
Convert a supported MKV recording before editing it in ChatCut.
Share one soundtrack while retaining the original multi-track MKV.
Keep editing
Add your downloaded file in ChatCut to trim it, add captions or make a vertical cut. Manual editing and export do not use credits; built-in Agent requests do.
Skills
100+ Skills. No experience needed. Start in one click.
FAQ
Yes, when its primary video is H.264 and its primary audio is AAC. Other supported codecs are re-encoded for this tool’s MP4 output.
No. Subtitle tracks and attachments are not carried into the MP4. Keep the MKV if you need them, or add new captions in ChatCut afterward.
This tool uses the primary audio track and has no track picker. Choose the desired soundtrack in a desktop converter first if the default is not right.
MKV can hold many codecs, and some are not readable by your browser. An unsupported audio track also stops conversion rather than silently producing a muted result.
No. Codec, bitrate and duration determine most of the size. A container-only change usually saves little space.
Yes. Conversion on this page is free, needs no sign-up and adds no watermark. Continuing in ChatCut is separate: built-in Agent messages use credits; manual editing and export do not.
No. The conversion engine reads and writes media inside your browser. If you choose to continue in ChatCut, add the downloaded file there yourself.
Use a recent browser with WebCodecs. Files are limited to 128 MB, 5 minutes and 4096 × 2160 pixels; AVI is limited to 60 seconds, and codec support varies by browser.
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