How to Convert MKV to MP4 Online
Follow these three simple steps to convert MKV to MP4. No software installation required. Free and secure.
Select an MKV Video
Choose an MKV movie, recording, or downloaded video from your device.
Choose Video and Audio Settings
Keep the original resolution and frame rate or choose new values, then keep the automatic audio settings or select a sample rate and mono or stereo output.
Convert and Download
Start the conversion, review the original and output file sizes, and download the completed MP4 video.
How Does the MKV to MP4 Converter Work?
The CompressFly MKV to MP4 converter reads the supported video and audio streams in the Matroska file, re-encodes the picture as H.264 and available audio as AAC, and stores them in an MP4 container. Subtitle streams are not copied to the MP4 output.
Conversion runs directly in your browser. Your MKV video is not uploaded to a server, and the completed MP4 file downloads from the browser to your device.
What "directly in your browser" means
- Your MKV video is not uploaded to a server.
- Video conversion runs locally on your device.
- The completed MP4 video downloads directly from your browser.
When to Convert MKV to MP4
Create an MP4 copy when an MKV video needs broader playback or upload compatibility and you do not need subtitles carried into the result.
Play MKV on More Devices
Convert an MKV file for a phone, tablet, television, or player that accepts MP4 more consistently.
Prepare Video for Upload
Create an MP4 copy for a website, social platform, presentation tool, or editor that rejects MKV files.
Make a Compatibility Copy
Keep the source MKV and download a separate H.264 MP4 for everyday sharing and delivery.
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MKV to MP4 Converter FAQ
How do I convert MKV to MP4 online?
Use this online MKV to MP4 converter in three steps: 1. Select an MKV video from your device. 2. Keep or change the available video and audio settings. 3. Start the conversion and download the completed MP4 video.
What happens when I convert MKV to MP4?
The converter re-encodes supported MKV video as H.264 and available audio as AAC inside a new MP4 file.
Can I change the video resolution and frame rate?
Yes. Keep the source resolution and frame rate or select an available output resolution and frame rate before conversion.
Will converting MKV to MP4 make the file smaller?
Not necessarily. The output size depends on the source video, selected resolution, frame rate, audio settings, duration, and visual content. Use the Video Compressor when reducing file size is the main goal.
Is the MKV to MP4 converter free?
Yes. Convert MKV to MP4 for free with no registration or credit card required.
Is there a file size limit, and is my video uploaded?
Your video is processed locally in your browser and is not uploaded to a server, so there is no server upload limit. The practical limit depends on your device's available memory and processing power, as well as the video's duration and resolution.