MKV to MP4 Converter
Convert MKV videos to MP4 format.
Drop your MKV file here
or click to browse · max 500 MB
Settings
Slower = better compression, longer conversion time
128k for speech · 192k for general use · 320k for music
FFmpeg WASM (~25MB) will be downloaded on first use and cached by your browser.
MKV to MP4 Converter
Converts Matroska (MKV) video files to MP4 format. MKV is a popular container for movies and TV shows, supporting multiple audio tracks and subtitles. MP4 offers broader device compatibility while maintaining quality.
What is it used for?
- Playing videos on smart TVs, Chromecast, and media players that don't support MKV
- Uploading to video platforms that require MP4
- Simplifying files with multiple audio tracks to a single track
- Mobile device playback on phones and tablets
- Streaming and sharing video files
Step-by-Step Guide
- Click upload or drag and drop your MKV file
- Adjust quality and encoding settings in the settings panel
- Click 'Convert to .MP4' - larger files may take several minutes
- Preview the converted video
- Download the universally compatible MP4 file
How it works
Upload an MKV file. FFmpeg re-encodes video to H.264 and audio to AAC in an MP4 container. Preview the result and download. Multiple audio tracks will be merged to a single stereo track.
Tips & Best Practices
- MKV files from streaming rips often use H.264 already, so conversion mainly re-muxes with minimal quality loss
- For large MKV files (1GB+), consider using desktop software for faster conversion
- If the original MKV has high bitrate, use CRF 20-22 to preserve quality
Frequently Asked Questions
Will subtitles be preserved?
Subtitles embedded in MKV files are not carried over to MP4 in this tool. If you need subtitles, use a dedicated subtitle tool or video editor.
What happens to multiple audio tracks?
FFmpeg uses the first (default) audio track and encodes it as AAC. Additional audio tracks in the MKV are not included in the MP4 output.
Can I convert 4K MKV files?
Yes, but 4K files are large and conversion will take significant time in the browser. For best results, keep files under 500MB.
Privacy & Security
This tool uses FFmpeg compiled to WebAssembly (WASM). The WASM binary (~25MB) is downloaded from a CDN on first use and cached by your browser. All file processing happens locally on your device - your files are never uploaded to any server. This makes it safe for sensitive, private, or confidential media files. Large files may take longer to process depending on your device's CPU and available memory.