MKV to MP4 Converter
Convert MKV to MP4 online for free. Fast, secure, and high-quality conversion with no sign-up or software required.
Maximum file size is 1GB
How it works
Three steps to your converted file
Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.
Upload your file
Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.
Choose an output format
Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.
Convert & download
Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.
What is an MKV file?
The Matroska Video (MKV) file is an open-standard, free container format capable of holding an unlimited number of video, audio, picture, or subtitle tracks in one file. Unlike proprietary containers, Matroska is structured upon Extensible Binary Meta Language (EBML), allowing for significant flexibility and forward compatibility. It supports a vast array of codecs, including H.264, VP9, HEVC, AAC, Vorbis, and FLAC, and is particularly noted for its support of soft subtitles (SSA/ASS) and chapter entries, making it a standard for high-definition video distribution (HD) and anime fansubs.
How to open an MKV file
Native support for MKV is available in Windows 10/11 via the Movies & TV app and generally on Linux distributions. macOS requires third-party software, as QuickTime Player does not natively parse the Matroska container. The industry-standard solution for all operating systems is VLC Media Player, which includes built-in libraries for decoding the diverse codecs often encapsulated within MKV files. Alternative options include MPV and MPC-HC (Windows).
MKV Technical Info
- Full Name
- Matroska Video Container
- Developed By
- Matroska (non-profit)
- Initial Release
- 2002
- MIME Type
- video/x-matroska
What is an MP4 file?
MPEG-4 Part 14 (MP4) is a digital multimedia container format defined by ISO/IEC 14496-14. Based directly on the QuickTime File Format (QTFF), it allows for streaming over the Internet and is the global standard for video compatibility. An MP4 file can store video streams (encoded with H.264/AVC, H.265/HEVC, or MPEG-4 Visual), audio streams (typically AAC or MP3), subtitles, and still images. It utilizes object-oriented structures specifically designed to support initial object descriptors (IOD) and other MPEG features.
How to open an MP4 file
MP4 is the most widely supported video format in existence. It opens natively on virtually all modern operating systems including Windows (via Movies & TV or Windows Media Player), macOS (QuickTime), Android, and iOS. Web browsers (Chrome, Firefox, Safari) also support native MP4 playback via the HTML5 video tag. No external software is generally required, though VLC Media Player is useful for MP4 files containing obscure codecs.
MP4 Technical Info
- Full Name
- MPEG-4 Part 14
- Developed By
- ISO / IEC
- Initial Release
- 2001
- MIME Type
- video/mp4
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Why RunConvert
The fastest way to convert any file
Purpose-built for speed, privacy, and breadth of format support.
Convert MKV to MP4 in seconds
Every MKV to MP4 conversion runs on our servers, so your device stays fast and the output quality stays intact.
Fast, cloud-powered
No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.
Secure & private
Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.
Free - no account needed
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Developer API
Convert MKV to MP4 via API
Automate MKV to MP4 conversions in three steps: create a job, upload your file, then poll for the result.
# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"tag": "mkv-to-mp4",
"tasks": {
"upload-file": {
"operation": "import/upload"
},
"convert": {
"operation": "convert",
"input": "upload-file",
"output_format": "mp4"
},
"export-result": {
"operation": "export/url",
"input": "convert"
}
}
}'
# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.mkv
# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
-H "Authorization: Bearer YOUR_API_KEY"Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.
FAQ
Frequently asked questions
Common questions about converting MKV to MP4 with RunConvert.
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