Convert MKV to MP4
Convert MKV videos to MP4 format instantly in your browser. Keep your video quality while gaining universal device compatibility. No upload needed, 100% private.
Drag 'n' drop files here, or
click to select files
.mkv
Drop your files and click Convert to get MP4
//when_to_use
When to Convert MKV to MP4
- Playing MKV movies on iPhone, iPad, or Apple TV which don't support MKV natively
- Uploading videos to YouTube, Instagram, or TikTok that reject MKV file uploads
- Streaming MKV files to Chromecast or Roku devices that only support MP4 playback
- Editing MKV footage in iMovie or CapCut which don't import MKV files
- Sharing video files with colleagues who use devices or software that can't handle MKV format
//comparison
MKV vs MP4
| Property | MKV | MP4 |
|---|---|---|
| Container | Matroska (.mkv) | MPEG-4 (.mp4) |
| Video codec support | Any (H.264, H.265, VP9, AV1) | H.264 (re-encoded) |
| Audio codec support | Any (AAC, DTS, FLAC, AC3) | AAC |
| Subtitle tracks | Multiple embedded tracks | Not supported |
| Device compatibility | PC, some Smart TVs | Universal |
| Streaming | Limited | Optimized (faststart) |
//how_it_works
How It Works
Drop your MKV video
Drag and drop or select an MKV file. Any codec combination is supported — H.264, H.265, VP9, DTS, FLAC, etc. First use loads FFmpeg WASM (~30MB).
FFmpeg demuxes MKV container
FFmpeg WASM reads the Matroska container in your browser, identifying all video, audio, and subtitle streams. The primary video and audio tracks are selected for conversion.
Re-encode to H.264 + AAC
Video is re-encoded using libx264, audio as AAC. The +faststart flag is applied for optimized web streaming. Subtitles are not embedded in the MP4 output.
Download universal MP4
Your MP4 plays on every device — phones, tablets, Smart TVs, game consoles, and all social media platforms. No special apps or codecs needed.
// under the hood
MKV (Matroska) is an open container supporting virtually any codec combination — commonly H.264/H.265 video with AAC/DTS/FLAC audio plus subtitle tracks. Our converter uses FFmpeg WASM to demux the MKV container, re-encode video as H.264 (libx264) and audio as AAC into an MP4 container. The +faststart flag optimizes for progressive web playback. Subtitle tracks are not carried over.
//faq
Frequently Asked Questions
- What is MKV format?
- MKV (Matroska Video) is an open container format that can hold virtually any combination of video, audio, and subtitle tracks. It's popular for high-quality video content but lacks widespread device support compared to MP4, especially on phones and Smart TVs.
- Why convert MKV to MP4?
- While MKV is flexible, many devices and platforms don't support it. iPhones, most Smart TVs, and social media platforms require MP4. Converting MKV to MP4 ensures your video plays everywhere without installing special apps or codecs.
- Does the conversion affect quality?
- The video is re-encoded from the MKV codec to H.264, and audio to AAC. Quality is maintained at a high level. If the MKV already contains H.264 video, the re-encoding preserves quality while switching the container format.
- What about subtitles in MKV?
- MKV files often contain embedded subtitle tracks. During conversion to MP4, soft subtitles are not carried over since they require the Matroska container. The video and primary audio track are fully preserved.
- Is my video private during conversion?
- Yes. Your video is processed entirely in your browser using FFmpeg WebAssembly. Nothing is uploaded to any server. The entire conversion happens on your device with zero network access to your files.