MKV to MP4 Converter

Convert a Matroska .mkv into an MP4 that plays on any device and app. Runs on your device — nothing is uploaded.

Drop your file here, or click to choose Processed privately in your browser — nothing is uploaded

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100% private. Your file is processed in your browser with ffmpeg (WebAssembly) and is never uploaded. Big or long files take longer and use more memory — for those, trim first.

How to Use the MKV to MP4 Converter

Three steps, all in your browser.

1

Load your MKV

Drag a .mkv file onto the box or click to choose one. MKV is common for downloaded or ripped video.

2

Convert to MP4

Click Convert. The tool re-encodes the video to H.264 and the audio to AAC inside an MP4 container.

3

Download the MP4

Preview and download the .mp4 — ready to play on phones, TVs and the web, and to upload to sites that reject MKV.

Frequently Asked Questions

How do I convert MKV to MP4?
Load your .mkv file and click Convert. The tool repackages and re-encodes it to an MP4 with H.264 video and AAC audio, entirely in your browser. When finished you can preview and download the MP4 — no software to install and nothing uploaded.
Why won’t my MKV play, and does MP4 fix it?
Many devices, browsers and social platforms don’t support the Matroska (MKV) container even when the video inside is standard. Converting to MP4 with H.264/AAC — the most widely supported combination — makes the clip play in Safari, on iPhones, on smart TVs and on sites that reject .mkv uploads.
Is my video uploaded anywhere?
No. Everything runs locally with ffmpeg compiled to WebAssembly, so your file is never uploaded, logged or stored. This is ideal for large personal videos, and it keeps working offline once the page has loaded.
How long does it take?
It depends on the length and resolution of the video and your device. Because the work happens in your browser, a long 1080p or 4K movie can take a while. Shorter clips convert quickly.
Will subtitles or extra audio tracks be kept?
The tool keeps the main video and audio track for maximum compatibility. Embedded subtitle tracks and secondary audio streams in the MKV are not carried across, which is what most people want for a clean, playable MP4.

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