MKV to MP4 Converter – Free & No Upload
Convert Matroska MKV files to MP4 locally in your browser — your video never leaves your device
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.
How to convert MKV to MP4
- Choose or drag in your MKV file — nothing is uploaded, it stays on your device.
- Click Start. H.264 sources are rewrapped losslessly in seconds; other codecs are re-encoded to H.264 in your browser.
- Download your MP4.
Frequently asked questions
What happens to subtitles and extra audio tracks?
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.
Is my video uploaded to a server?
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.
What is the maximum file size?
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.