MKV to MP4 Converter – Free, Fast & Private
Convert Matroska MKV files to MP4 locally in your browser — your video never leaves your device
How to convert MKV to MP4
Choose or drag in your MKV file — nothing is uploaded, it stays on your device.
Click Start Converting — H.264 sources are rewrapped losslessly in seconds; other codecs are re-encoded to MP4 (H.264/AAC).
Download your standard MP4 file.
About MKV to MP4 conversion
MKV is a flexible container popular for screen recordings and downloads, but phones, TVs, editors and messengers often refuse it. This tool converts MKV to a standard MP4 entirely in your browser.
If the MKV already holds H.264 video it is rewrapped without re-encoding — lossless and finished in seconds. HEVC, VP9 or other codecs are re-encoded to H.264 for maximum compatibility.
Frequently asked questions
MP4 output keeps the video track and the first audio track. Embedded subtitle tracks and additional audio languages are not carried over — convert with the audio track you need as the first one.
Yes. HEVC, VP9 and other codecs inside MKV are decoded and re-encoded to H.264 in your browser. MKVs that already hold H.264 video are simply rewrapped — lossless and done in seconds.
No. The conversion runs entirely in your browser using WebAssembly (FFmpeg). Your file never leaves your device — that is also why there is no upload wait, no queue and no file-size pricing.
Up to 8GB on desktop browsers and 2GB on mobile. There is no limit on the number of files you convert, and no signup or watermark.
Yes — completely free and unlimited, with no watermark, no signup and no daily quota. Because the conversion runs on your own device instead of our servers, there are no processing costs to charge for.
If the source already contains H.264 video, the file is rewrapped without re-encoding and finishes in seconds, even for gigabyte files. Other codecs are re-encoded in parallel WebAssembly workers, which runs at roughly real-time speed on a modern computer.
Yes. It runs in any modern browser — Chrome, Safari, Edge or Firefox — on Windows, macOS, ChromeOS, Linux, iOS and Android. There is nothing to install.
AAC and MP3 audio is copied over unchanged. Other audio codecs (PCM from cameras, Vorbis, Opus…) are converted to AAC so the resulting MP4 plays everywhere.