How to Convert MKV to MP4
- Add your video — Drag and drop an MKV file into the upload area, or click "browse files" to select one from your computer.
- Wait for conversion — The converter engine loads automatically (about 31MB on first use, cached for future visits). Your video converts right in your browser.
- Download — Click "Download MP4" to save the converted file. The original quality is preserved.
What is an MKV File?
MKV (Matroska Video) is a popular open-source container format that can hold an unlimited number of video, audio, subtitle, and metadata tracks in a single file. It's widely used for high-definition video content because of its flexibility and support for virtually every codec.
Why Convert MKV to MP4?
While MKV is technically superior as a container format, MP4 is the universal standard that works on every device. If you've ever tried to play an MKV file on your iPhone, smart TV, or in a web browser and gotten an error, that's why. MP4 files play natively on iPhones, iPads, Android devices, smart TVs, game consoles, and in every web browser. Converting to MP4 doesn't change the video or audio quality — it simply repackages the content into a more compatible container.
Is the Quality Preserved?
Yes. When the video codec is already MP4-compatible (like H.264 or H.265), the converter remuxes the file — meaning it copies the video and audio streams directly without re-encoding. This is fast and produces an identical-quality output. If re-encoding is needed, the converter uses high-quality settings to minimize any quality loss.
Supported Input Formats
.mkv
Supports MKV files with common video codecs (H.264, H.265, VP8, VP9) and audio codecs (AAC, MP3, Opus, FLAC, AC3). Subtitle tracks are not included in the MP4 output.
Frequently Asked Questions
Is this MKV to MP4 converter free?
Yes, completely free. No sign-up, no hidden fees, no watermarks. Convert as many videos as you need.
Are my videos uploaded to a server?
No. All processing happens locally in your browser using WebAssembly (ffmpeg.wasm). Your files never leave your device. We never see, store, or have access to your files.
How long does the conversion take?
The first time you use the tool, it downloads the converter engine (~31MB). This is cached by your browser for future visits. The actual conversion time depends on your file size and device — most files under 200MB convert in under a minute.
Is there a file size limit?
There's no hard limit, but since conversion happens in your browser's memory, very large files (over 500MB) may be slow or cause issues. For best results, keep files under 500MB.
Will the video quality be the same?
Yes. The converter remuxes (directly copies) the video and audio streams when possible, preserving the original quality. If the codecs need to be changed, it uses high-quality encoding settings.
What devices does this work on?
This converter works on any device with a modern web browser — Windows, Mac, Chromebook, and Linux. Mobile devices may have limited memory for large files. No software to install.
What is an MKV file?
MKV (Matroska Video) is a flexible container format that can hold multiple video, audio, and subtitle tracks in one file. It's popular for high-quality video but isn't supported natively by many devices and apps. Converting to MP4 ensures your video plays everywhere.